Explanation:

A father is three times as old as his son. After fifteen years the father will be twice as old as his son's age at that time . Hence the father's present age is -- Correct Answer 45 Let the present age of the father and his son be F and S respectively. Now, F = 3S Again, F + 15 = 2(S + 15) or,  3S + 15 = 2S + 30 or, 3S - 2S = 30 - 15 or, S = 15 So,  F = 3S = 3 × 15 =  45 years

Explanation:

An empty swimming pool can be filled to capacity through an inlet pipe in 3 hours, and it can be completely drained by a drainpipe in 6 hours . If both pipes are fully open at the same time , in how many hours will the empty pool be filled to capacity? Correct Answer 6 Inlet pipe fill 1/3 part of the pool in 1 hour Drain pipe drains 1/6 part of the pool in 1 hour So, together they fill (1/3 - 1/6 = 1/6) part of the pool in 1 hour So, together they will fill the pool completely in 6 hours [Shortcut : (Inlet×Outlet) / (Outlet - Inlet) = (3×6) / (6 - 3) = 6 hr]

Explanation:

If a rectangle's length and width are both doubled, by what percent is the rectangle's area increased? Correct Answer 300% Let the initial length and width be L and W respectively. Initial area = L×W New length = 2L New width = 2W New area = 2L×2W = 4 L×W Increase in area = (4 L×W - L×W) / (L×W) × 100% = 300%

Explanation:

A rectangular tank 10 inch by 8 inch by 4 inch is filled with water. If all of the water is to be transferred to cube-shaped tanks, each one 3 inches on a side, how many of these smaller tanks are needed? Correct Answer 12 Volume of the rectangular tank = 10×8×4 = 320 in3 Volume of a smaller tank = 33  = 27 in3 Number of smaller tanks needed = 320/27 ≈ 12

Explanation:

The length of a rectangle is 1 inch more than 2 times its width.The area of the rectangle is 36 square inches. what is the length of the rectangle? Correct Answer 9 inches Let the width be W. Then, Length = 2W + 1 Now, area,  (2W + 1)×W = 36 or, 2W2  + W = 36 or, 2W2  + W - 36 = 0 or, 2W2  + 9W - 8W - 36 = 0 or, W(2W + 9) - 4(2W + 9) = 0 or, (2W + 9)(W - 4) = 0 or, W - 4 = 0 [2W + 9≠0] or, W = 4 So, length, 2W + 1 = 2×4 + 1 =  9 inches

Explanation:

A box contains 90 nuts each of 100 gms an d 100 bolts each of 150 gms. If the entire box weighs 35.5 kgs , then the wight of the empty box is-- Correct Answer 11.5 kg Weight of the nut and bolts = 90×100 + 100×150 = 9000 + 15000 = 2400gm = 24 kg So, weight of the empty box = 35.5 - 24 = 11.5 kg

Explanation:

A wholesaler bought 1,200 radios for Tk. 18 each .The wholesaler sold 60 percent of the radios for Tk. 30 each and the rest for Tk. 15 each . what was the wholesaler's average profit per radio? Correct Answer Tk. 6 Cost price = 1200×18 = 21600 Revenue = (60% of 1200)×30 + (40% of 1200)×15 = 21600 + 7200 = 28800 Profit = 28800 - 21600 = 7200 Profit per radio = 7200 / 1200 = 6 TK

Explanation:

what is the original price of pack of milk powder which Zahid has bought for taka 100, after receiving a discount of 20% ? Correct Answer Tk. 125 Let the original price be A. Then, A - 20% of A = 100 or, A - A/5 = 100 or, 4A/5 = 100 or, A = 100×5 / 4 = 125 TK

Explanation:

Saif , Noman and Morshed divided a sum of money among themselves in the ratio 2: 3: 7 Find the share of Saif if the total share of saif and Noman together is Tk. 1,500 less than that of Morshed. Correct Answer Tk. 1,500 Let their shares be 2x, 3x and 7x respectively. ATQ,  7x - (2x + 3x) = 1500 or,  7x - 5x = 1500 or,  2x = 1500 So, share of Saif is 1500 TK.

Explanation:

what is the total interest on Tk. 800 at 12.5 % per annum for 9 months in taka? Correct Answer 75 Interest,  I = P n r Here,   P = 800 TK,   n = 9/12 year,    r = 12.5/100 = 1/8 So,  I = 800 × 9/12 × 1/8 = 75 TK

Explanation:

Two identical taps fill 2/5 of a tank in 20 minutes.when one of the taps goes dry n how many minutes will the remaining one tap fill the rest of the tank? Correct Answer 60 min 2 taps can fill in 20 minutes = 2/5th 1 tap can fill in 20 minutes = 1/5th. remaining portion to be filled up = 1 - 2/5 = 3/5. 1/5th can be filled by 1 tap in 20 mins 3/5th can be filled by 1 tap in 20x3 mins = 60 minutes. (ans)

Explanation:

Last year there were 1172 students at Gulshan High school. This year there are 15 percent more students than last year. Approximately how many students are at Gulshan High School this year? Correct Answer 1348 Number of students this year = 1172 + 15% of 1172 =   1172 + 175.8 ≈ 1348

Explanation:

A portion of the 7,200 is invested at a 4% annual return , while the remainder is invested at a 5% annual return . If the annual income from both portions is the same, what is the total income from the two investments? Correct Answer Tk. 320 Let the investments be A and (7200 - A) respectively. Interest, I = P n r Now,  A × 1 × 4/100 = (7200 - A) × 1 × 5/100 or, 4A = 5×7200 - 5A or, 5A + 4A = 36000 or, 9A = 36000 or, A = 4000 So, total income =  A × 1 × 4/100 + (7200 - A) × 1 × 5/100 = 4000×4/100 + (7200 - 4000)×5/100 = 160 + 160 = 320 TK

Explanation:

In a two digit number, if it is known that its unit's digit exceeds its ten's digit by 2 and that product of the given number and the sum of its digits is equal to 144, then the number is- Correct Answer 24 Let the ten's digit be x Then, unit's digit = x + 2 Number = 10x + (x + 2) = 11x + 2 Sum of digits = x + (x + 2) = 2x + 2 ∴ (11x + 2)(2x + 2) = 144 ⇒ 22x2 + 26x - 140 = 0 ⇒ 11x2 + 13x - 70 = 0 ⇒ 11x2 + (35 - 22)x - 70 = 0 ⇒ 11x2 + 35x - 22x - 70 = 0 ⇒ (x - 2)(11x + 35) = 0 ⇒ x = 2 Hence, required number = 11x + 2 = 24 (ans)

Explanation:

Two trains are moving in opposite directions at 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is - Correct Answer 48 Relative speed = (60 + 90) km/hr = 150 km/hr = 150×1000/3600 m/s = 41.67 m/s Total distance = (1.1 + 0.9) km = 2 km = 2000 m Time taken to cross each other = 2000/41.67 ≈ 48 seconds

Explanation:

Razia spent 3 hours climbing 6 miles up a hill. She spent 2 hours coming down the hill in a different path which had a length of 8 miles. For Razia's completed climb up and down the hil , what was her average speed, in miles per hour? Correct Answer 2.8 Average speed = total distance / total time = (6 + 8) / (3 + 2) = 14/5 = 2.8 miles/hr

Explanation:

In a 500 m race the ratio of the speeds of two contestants Ajmal and Badal is 3:4 . If Ajmal has a head start of 140 km then Ajmal wins by- Correct Answer 60m To reach the winning post Ajmal will have to cover a distance of (500 - 140)m = 360 m. While Ajmal covers 3 m, Badal covers 4 m. While Ajmal covers 360 m, Badal covers (4/3×360)m = 480 m. Thus, when Ajmal reaches the winning post, Badal covers 480 m and therefore remains 20 m behind. ∴ Ajmal wins by 20 m. (ans)

Explanation:

If 'n' is a natural number, then (6n2+6n) is always divisible by- Correct Answer 6 only Here, 6n2 + 6n = 6(n2 + n) which is always divisible by 6.

Explanation:

Two pipes A & B would fill a tank in 20 & 30 minutes respectively. Both pipes being open, find when A must be turned off so that tank may be just filled in 15 minutes. Correct Answer After 10 minutes Let the time be T minutes after which pipe A need to turned off. Both of the pipes remain open together only for T minutes. Pipe A fills 1/20 of the tank in 1 minute. Pipe B fills 1/30 of the tank in 1 minute Together in 1 minute they fill (1/20 + 1/30 = 1/12) of the tank. Together in T minutes they fill = T/12 of the tank In (15 - T) minutes, pipe B alone can fill = (15 - T)/30 of the tank Now, T/12 +  (15 - T)/30 = 1 or,  {15T + 6(15 - T)}/180 = 1 or, (15T + 90 - 6T) / 180 = 1 or,  9T = 180 - 90 or,  9T = 90 So, T =  10 minutes

Explanation:

Divide Rs. 5625 among A, B & C so that A may receive 1/2 as much as B & C and B 1/4 of what A and C together receive? Correct Answer 1875, 1125, 2625 Let they receive A, B & C Rs. respectively. Now, A = (B + C) / 2 or,  2A = B + C - - - - - - - - - - (i) Again, B = (A + C) / 4 or, 4B = (A + C) or, 4B = (B + C) / 2 + C or, 4B = B/2 + C/2 + C or, 4B - B/2 = 3C/2 or, 7B/2 = 3C/2 or, B = 3C/7 - - - - - - - (ii) Now, 2A = 3C/7 + C  [from (i)] or, 2A = 10C/7 or, A = 5C/7 - - - - - - (iii) From (ii) and (iii),  B : C = 3 : 7 C : A = 7 : 5 So,  A : B : C = 5 : 3 : 7 A will receive = 5 / (5 + 3 + 7) × 5625 =  1875 Rs. B will receive = 3 / (5 + 3 + 7) × 5625 =  1125 Rs. C will receive = 7 / (5 + 3 + 7) × 5625 =  2625 Rs.

Explanation:

What percentage of profit is made by selling an article at a certain price if by selling at two third of that price there would be a loss of 20%? Correct Answer 20% Let the cost price and sell price be A and S respectively. ATQ,   (A - 2S/3) /A = 20/100 or,  (A - 2S/3) / A = 1/5 or, (A - 2S/3) = A/5 or, 2S/3 = A - A/5 or, 2S/3 = 4A/5 or, S = 4A/5 × 3/2 or, S = 6A/5 Now, profit = (S - A) / A × 100%   = (6A/5 - A) / A × 100% = (A/5) / A × 100% =  20%

Explanation:

Business partnera A, B and C agree to divide their total profit for the year in the ratios 4 : 7 : 8 respectively. If A's share of the profit is Rs. 16,000, what was the total profit of the business partners for the year? Correct Answer Rs. 76,000 Let the total profit be P. Now, A's share of profit, 4 / (4 + 7 + 8) × P = 16000 or, 4P/19 = 16000 or, P = 16000 × 19 / 4 = 76000 Rs.

Explanation:

Income of A is 25% less than B. How much percent B's income would be more than that of A? Correct Answer 33.5% Let their income be A and B respectively. Now,  A = B - 25% of B = B - B/4 = 3B/4 or,  B = 4A/3 Now,  B - A = 4A/3 - A = A/3 = A/3 × 100% = 33.33% of A

Explanation:

Nazir can wash his car 15 minutes while his son takes twice as long. If they work together how many minutes will the job take them? Correct Answer 10 His son can wash the car in (15 × 2 = 30) minutes Nazir can wash 1/15 part of the car in 1 minute His son can wash 1/30 part of the can in 1 minute Together they can wash (1/15 + 1/30 = 1/10) part of the car in 1 minute So, together they can wash the whole car in 10 minutes.

Explanation:

A glass when full of milk, weighs one kilogram. When half full, it weighs 3/4 kilogram. What is the weight of the empty glass? Correct Answer .5 kg Weight of 1/2 glass of milk = 1 - 3/4 = 1/4 kg So, weight of full glass of milk = 2 × 1/4 = 1/2 kg So, weight of the glass = 1 - 1/2 = 1/2 kg = 0.5 kg

Explanation:

If Rs. 450/- amount to Rs. 504/- in three years at simple interest, what will Rs. 650/- amount in 2 years & 6 months the interest rate being the same in both cases? Correct Answer Rs. 715/- Here, 2 year 6 months = 2.5 years Principal with simple interest, A = P( 1 + n r) Now, 504 = 450( 1 + 3 × r) or,  1 + 3r = 504/450 or, 3r = 504/450 - 1 or, 3r = (504 - 450) / 450 or, 3r = 54 / 450 or, r = 54 / (450 × 3) or, r = 1/25 Again,  A = 650( 1 + 2.5 × 1/25) or, A = 650 × (25 + 2.5)/25 or, A = 650 × 27.5 / 25 So, A = 715 Rs.

Explanation:

In a right angled triangle the horizontal side measures 8 cm and the vertical side measures 12 cm. What is the area of the triangle? Correct Answer 48 sq cm Area of triangle = 1/2 × base × height = 1/2 × 8 × 12 = 48 cm2

Explanation:

A batsman in his 17th innings makes a score of 85 and thereby increases his average by 3, his average after the 17th innings is : Correct Answer 37 Let the average of the first 16 innings be A. Total of the 16 innings = 16A New average = A + 3 New total of 17 innings, 17(A + 3) = 16A + 85 or,  17A + 51 = 16A + 85 or,  17A - 16A = 85 - 51 or, A = 34 So, new average after 17th innings = A + 3 = 34 + 3 = 37

Explanation:

A man travels 100 miles at 20 miles per hour, 60 miles at 30 miles per hour and 80 miles at 10 miles per hour, what is his average rate for the three trips? Correct Answer 16 miles per hr Time travelled at 20 miles//hr = 100/20 = 5 hrs Time travelled at 30 miles//hr = 60/30 = 2 hrs Time travelled at 10 miles//hr = 80/10 = 8 hrs Total time travelled = 5 + 2 + 8 = 15 hrs Total travelled = 100 + 60 + 80 = 240 miles Average rate = 240 / 15 = 16 miles per hour

Explanation:

A sum of Rs. 1500.00 was put in two companies, one paid 6% simple interest and the other 5%. The whole annual interest from the two companies was Rs.85.00. What is the sum invested in the first company? Correct Answer Rs. 1000 Let the investments be F and (1500 - F) Rs. in the companies respectively. Interest, I = P n r Now, F × 1 × 6/100 + (1500 - F) × 1 × 5/100 = 85 or, 6F + 7500 - 5F = 8500 [multiplying both sides by 100] or, F = 8500 - 7500 or, F = 1000 Rs.

Explanation:

A sum of 24 is divided into two parts so that seven times the first part added to five times the second part makes 146. The value of first part is? Correct Answer 13 Let the value of first and second part be F and (24 - F) respectively. Now, 7F + 5(24 - F) = 146 or, 7F + 120 - 5F = 146 or, 2F = 146 - 120 or, F = 26/2 =  13

Explanation:

How many signals can be given by 5 flags of different colours using 3 flags at a time. Correct Answer 60 Possible ways = 5P3 = 5 × 4 × 3 = 60 [Ways of choosing 3 flags from 5 flags is 5C3. But different signals can be given bay rearranging those 3 flags in 3! ways. So, total possible ways of giving signal =  5C3× 3! =  5P3]

Explanation:

Which of the following is a solution to the equation x+x2=1 --- Correct Answer None of these x+2x=1 or, x=⅓ as there is no right answer, so the answer will be none of these.

Explanation:

If the average of 5 consecutive integers is 12, find the smallest integer. Correct Answer 10 The third number is the average number of 5 consecutive integers. So, the smallest integer is = 12 - 2 = 10

Explanation:

What is the area of a circle with a radius of 7 meters? Correct Answer 154 sq metres Area = π R2 = 22/7 × 72 = 154 m2

Explanation:

Complete the series 1, 9, 17, 25, 33------ Correct Answer 41 1 + 8 = 9 9 + 8 = 17 17 + 8 = 25 25 + 8 = 33 33 + 8 = 41

Explanation:

Kibria went to the swtationers and bought things worth Tk 25 out of which 30 paisa was sales tax on taxable items. If the tax rate is 6% , then what was the cost of the tax free items? Correct Answer Tk 19.70 Let the amount taxable payments be Tk. x According to question, 6% of x = 30/100 x = (30/100 ×100/6 x = 5 Cost of tax free items = [ 25 - (5 + . 30)] = tk.19.70

Explanation:

If 2x=7 and 3y=2, then what is the value of 9xy? Correct Answer 21 (2x)(3y) = 7×2 = > 6xy = 14 Multiply both sides by 3/2 ∴9xy = 21

Explanation:

If the length of a rectangle is increased by 20% and the width is decreased by 20%, then the area is : Correct Answer decreased by 4% We can let L = the original length and W = the original width Thus, the original area of the rectangular is LW and the new area is 1.2L× 0.8W = 0.96LW So, the area is decreased by 4%

Explanation:

A towel, when bleached, was found to have lost 20% of its length and 10% of its breath . what is the percentage of decrease in area? Correct Answer 28% Let, original length = x and original breadth = y Decrease in area = xy - ( 80x/100×90y/100) = ( xy - 18xy/25) = 7xy/25 Decrease % = ( 7xy/25 ×1/xy ×100%) = 28%

Explanation:

An industrial loom weaves 0.128 metres of cloth every second. Approximately , how many seconds will it take for the loom to weave 25 metres of cloth? Correct Answer 195 25 ÷ 128 = 195.3125 seconds

Explanation:

Complete the series 4, 9, 17, 35,------ Correct Answer 69 4 × 2 + 1 = 9 9 × 2 - 1 = 17 17 × 2 + 1 = 35 35 × 2 - 1 = 69

Explanation:

How much would I have to pay for a book which cost Rs. 72 to produce, if the printing company sold it to a book seller at 20% profit and the bookseller sold it to me at a profit of 25%? Correct Answer Rs. 108 Book seller's buying price = 72 + 20% of 72 = 72 + 14.4 = 86.4 Rs. Book seller's selling price = 86.4 + 25% of 86.4 = 108 Rs.

Explanation:

A farmer has two rectangular fields. The larger field has twice the length and four times the width of the smaller field. If the area of the smaller field is K units, what is the area of the larger field? Correct Answer 8K Let the length and width of the smaller field be L and W respectively. So, area of the smaller field, K = L×W Now, area of the larger field = 2L×4W = 8 L×W = 8K

Explanation:

On selling 17 balls for Tk 720 , there iss a loss equal to the cost price of 5 balls. The cost price of a ball is -- Correct Answer Tk 60 (Cost price of 17 balls) - ( selling price of 17 balls) = ( cost price of 5 balls) Cost price of 12 balls = selling price of 17 balls = Tk.720 Cost price of 1 ball = Tk 720/12 = Tk.60

Explanation:

If 12 years are added to 2/3 age of Rani, she will be three years older than today. What is Rani's present age? Correct Answer 27 Let the present age of Rani be R. Now, 2R/3 + 12 = R + 3 or, R - 2R/3 = 12 - 3 or, R/3 = 9 or, R = 27 years

Explanation:

If an integer Y is subtracted from an integer X and the result is greater than X, then Y must be --- Correct Answer Less than O x - y > x x = 1 এবং y = - 1 হলে, x - y = 1 - ( - 1) = 2>1 x = 1 এবং y = - 2 হলে, x - y = 1 + 2 = 3 >1 y <0 হলে x - y > x শর্তটি সিদ্ধ হয়।