Three pipes A, B, C fill a tank in 12, 15, and 20 hours respectively. All three working together will fill the tank in approximately how many hours?

The correct answer is B: 4.6 hours. Combined rate = 1/12 + 1/15 + 1/20 = (5+4+3)/60 = 12/60 = 1/5. Wait: LCM(12,15,20)=60. 1/12 = 5/60, 1/15 = 4/60, 1/20 = 3/60. Sum = 12/60 = 1/5. Time = 5 hours. But let me recalculate: (1/12 + 1/15 + 1/20). LCM = 60. = 5/60 + 4/60 + 3/60 = 12/60 = 1/5. So time = 5 hours which is option C, not B. Rev

A pipe fills a tank in 10 hours and another empties it in 15 hours. If both start simultaneously, when will the tank be filled?

The correct answer is B: 30 hours. Fill rate = 1/10, Empty rate = 1/15. Net = 1/10 - 1/15 = 1/30. Time = 30 hours

A man buys 50 kg rice at Rs. 8/kg and sells at Rs. 10/kg. What's profit%?

The correct answer is B: 25%. CP = 50 × 8 = 400. SP = 50 × 10 = 500. Profit% = (500-400)/400 × 100 = 25%.

A batch of 60 workers can complete a project in 40 days. If 20 more workers join, in how many days will the project be completed?

The correct answer is C: 30 days. Total work = 60 × 40 = 2400 man-days. New workers = 80. Days = 2400/80 = 30 days

The GCD of two numbers is 12 and their LCM is 144. If one number is 36, find the other number.

The correct answer is A: 48. Using the property: GCD(a,b) × LCM(a,b) = a × b. Therefore: 12 × 144 = 36 × b. So 1728 = 36b, which gives b = 48.

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Quantitative Aptitude

Quantitative aptitude questions for competitive exams

428 Q 7 Topics Take Mock Test

Difficulty: All Easy Medium Hard 191–200 of 428

Topics in Quantitative Aptitude

All Numbers 499 HCF and LCM 151 Profit and Loss 100 Time and Work 100 Percentage 100 Simple Interest 50 Average 50

Q.191 Easy Numbers

A man buys 50 pens at Rs. 3 each and sells them at Rs. 3.50 each. What is his profit percentage?

A 14.28%

B 16.67%

C 18.5%

D 20%

Correct Answer: B. 16.67%

EXPLANATION

CP = 50 × 3 = 150. SP = 50 × 3.5 = 175. Profit % = (25/150) × 100 = 16.67%.

Test

Q.192 Easy Numbers

A number when increased by 15% becomes 575. What is the original number?

A 500

B 550

C 460

D 480

Correct Answer: A. 500

EXPLANATION

Let original number = x. x × 1.15 = 575. x = 575/1.15 = 500.

Test

Q.193 Easy Numbers

A person invested Rs. 10000 in a scheme. After 2 years at 10% compound interest, the amount becomes:

A Rs. 12100

B Rs. 12000

C Rs. 11000

D Rs. 11500

Correct Answer: A. Rs. 12100

EXPLANATION

Amount = P(1 + R/100)^T = 10000(1.1)^2 = 10000 × 1.21 = Rs. 12100.

Test

Q.194 Easy Numbers

A boat takes 4 hours to travel 48 km downstream and 6 hours to travel the same distance upstream. What is the speed of the current?

A 1 km/h

B 2 km/h

C 3 km/h

D 4 km/h

Correct Answer: B. 2 km/h

EXPLANATION

Downstream speed = 48/4 = 12 km/h. Upstream speed = 48/6 = 8 km/h. Current speed = (12 - 8)/2 = 2 km/h.

Test

Q.195 Easy Numbers

Simple Interest on Rs. 5000 at 8% per annum for 2.5 years is:

A Rs. 800

B Rs. 900

C Rs. 1000

D Rs. 1200

Correct Answer: C. Rs. 1000

EXPLANATION

SI = (P × R × T) / 100 = (5000 × 8 × 2.5) / 100 = 100000/100 = Rs. 1000.

Test

Q.196 Easy Numbers

A pipe can fill a tank in 6 hours and empty it in 10 hours. If both pipes are opened together, how long will it take to fill the tank?

A 10 hours

B 15 hours

C 20 hours

D 25 hours

Correct Answer: B. 15 hours

EXPLANATION

Net rate = 1/6 - 1/10 = 5/30 - 3/30 = 2/30 = 1/15. Time = 15 hours.

Test

Q.197 Easy Numbers

If a man works alone, he can complete a task in 12 days. If his wife works alone, she can complete it in 18 days. Working together, in how many days will they complete the task?

A 7.2 days

B 8.4 days

C 9.6 days

D 10 days

Correct Answer: A. 7.2 days

EXPLANATION

Combined rate = 1/12 + 1/18 = 3/36 + 2/36 = 5/36. Time = 36/5 = 7.2 days.

Test

Q.198 Easy Numbers

A merchant buys articles at Rs. 80 each and sells them at a profit of 37.5%. What is the selling price?

A Rs. 110

B Rs. 115

C Rs. 120

D Rs. 125

Correct Answer: A. Rs. 110

EXPLANATION

SP = CP + Profit = 80 + (80 × 37.5/100) = 80 + 30 = Rs. 110.

Test

Q.199 Easy Numbers

A number is increased by 25% and then decreased by 20%. What is the net change in percentage?

A 0%

B 5%

C 10%

D 15%

Correct Answer: A. 0%

EXPLANATION

Let the number be 100. After 25% increase: 125. After 20% decrease on 125: 125 × 0.8 = 100. Net change = 0%.

Test

Q.200 Easy Numbers

A retailer buys goods at Rs. 450 per unit and sells at 40% profit. What is the selling price per unit?

A Rs. 590

B Rs. 600

C Rs. 630

D Rs. 650

Correct Answer: C. Rs. 630

EXPLANATION

SP = 450 × 1.40 = 630.

Test

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