Central Exam — Quantitative Aptitude
UPSC · SSC · Bank · Railway · NDA — Central Government Exam MCQ Practice
Showing 481–490 of 1,106 questions
Q.481
Easy
Numbers
A train crosses a pole in 8 seconds. If the length of the train is 160m, what is its speed in km/h?
Correct Answer:
C. 72 km/h
Explanation:
Speed = Distance/Time = 160/8 = 20 m/s = 20 × 3.6 = 72 km/h
Q.482
Easy
Numbers
Worker A completes a job in 15 days. Worker B completes the same job in 20 days. If they work together, how many days will it take?
Correct Answer:
C. 8.57 days
Explanation:
Combined rate = 1/15 + 1/20 = 7/60. Time = 60/7 ≈ 8.57 days
Q.483
Easy
Numbers
A merchant buys goods for Rs. 8000 and sells them at a loss of 15%. What is the selling price?
Correct Answer:
A. Rs. 6800
Explanation:
SP = CP × (1 - loss%) = 8000 × 0.85 = Rs. 6800
Q.484
Easy
Numbers
Two trains start from the same station at the same time. Train A travels at 60 km/h and Train B at 80 km/h in the same direction. After 3 hours, what will be the distance between them?
Correct Answer:
C. 60 km
Explanation:
Relative speed = 80 - 60 = 20 km/h. Distance = 20 × 3 = 60 km
Q.485
Easy
Numbers
The ratio of boys to girls in a class is 3:2. If there are 15 boys, how many girls are there?
Correct Answer:
B. 10
Explanation:
If boys:girls = 3:2 and boys = 15, then girls = (2/3) × 15 = 10
Q.486
Medium
Numbers
A number when increased by 20% becomes 480. What is the original number?
Correct Answer:
C. 400
Explanation:
Let original number = x. x × 1.20 = 480. x = 480/1.20 = 400
Q.487
Medium
Numbers
A pipe can fill a tank in 8 hours while another pipe can empty it in 12 hours. If both are opened simultaneously, in how many hours will the tank be filled?
Correct Answer:
C. 24 hours
Explanation:
Net rate = 1/8 - 1/12 = (3-2)/24 = 1/24. Time = 24 hours
Q.488
Medium
Numbers
A boat's speed in still water is 12 km/h and the speed of the current is 3 km/h. How long will it take to travel 45 km upstream?
Correct Answer:
B. 5 hours
Explanation:
Upstream speed = 12 - 3 = 9 km/h. Time = 45/9 = 5 hours
Q.489
Medium
Numbers
Rs. 10000 becomes Rs. 12100 in 2 years at compound interest. What is the rate of interest per annum?
Correct Answer:
B. 10%
Explanation:
12100 = 10000(1 + r/100)^2. (1 + r/100)^2 = 1.21. 1 + r/100 = 1.1. r = 10%
Q.490
Medium
Numbers
A sells his goods at 25% profit to B. B sells them at 20% profit to C. If C pays Rs. 3000, what is A's cost price?
Correct Answer:
A. Rs. 2000
Explanation:
A's CP × 1.25 × 1.20 = 3000. A's CP × 1.5 = 3000. A's CP = Rs. 2000