Showing 271–280 of 429 questions
A train travels at 72 km/h. How many metres does it cover in 25 seconds?
A
400 m
B
500 m
C
600 m
D
700 m
Explanation:
Speed in m/s = 72 × 5/18 = 20 m/s. Distance = 20 × 25 = 500 m
A boat's speed in still water is 15 km/h. Stream speed is 3 km/h. What is the ratio of downstream to upstream speed?
Explanation:
Downstream = 15 + 3 = 18. Upstream = 15 - 3 = 12. Ratio = 18:12 = 3:2
Cost price of an article is Rs. 500. It is sold at 24% profit. What is selling price?
A
Rs. 612
B
Rs. 620
C
Rs. 624
D
Rs. 630
Correct Answer:
C. Rs. 624
Explanation:
SP = 500 × 1.24 = Rs. 620. Wait, let me recalculate: 500 + (500 × 0.24) = 500 + 120 = 620. Correct answer should be B.
A shopkeeper marks goods at 60% above cost price. If he gives a discount of 25% on marked price, what is his profit percentage?
Explanation:
Let CP = 100. MP = 160. After 25% discount, SP = 160 × 0.75 = 120. Profit% = (120-100)/100 × 100 = 20%
A sum becomes 4 times itself in 15 years at simple interest. What is the rate of interest per annum?
Explanation:
If sum becomes 4 times, SI = 3P. SI = P×R×T/100 → 3P = P×R×15/100 → R = 20% p.a.
A person's salary increases by 15% and then decreases by 10%. What is the net change in his salary?
A
3.5% increase
B
5% increase
C
3.5% decrease
D
5% decrease
Correct Answer:
A. 3.5% increase
Explanation:
Let initial salary = 100. After 15% increase = 115. After 10% decrease = 115 × 0.90 = 103.5. Net change = 3.5% increase
A man invests ₹50,000 at 12% per annum SI for 2 years. If he had invested at CI instead, what additional amount would he earn?
A
₹720
B
₹1,200
C
₹1,440
D
₹2,000
Explanation:
SI = 50000×12×2/100 = ₹12,000. CI = 50000(1.12)² - 50000 = ₹12,720. Difference = ₹720.
Two pipes A and B fill a tank in 20 and 30 minutes respectively. A leak empties it in 60 minutes. How long to fill the tank with all three?
A
15 minutes
B
18 minutes
C
12 minutes
D
20 minutes
Correct Answer:
A. 15 minutes
Explanation:
Rate = 1/20 + 1/30 - 1/60 = 3/60 + 2/60 - 1/60 = 4/60 = 1/15. Time = 15 minutes.
A train 150m long crosses a platform of 250m in 20 seconds. Find its speed in km/h.
A
54 km/h
B
72 km/h
C
81 km/h
D
90 km/h
Correct Answer:
B. 72 km/h
Explanation:
Distance = 150 + 250 = 400m. Speed = 400/20 = 20 m/s = 20×3.6 = 72 km/h.
A boat covers 24 km upstream in 6 hours and 24 km downstream in 3 hours. Find the speed of the current.
A
2 km/h
B
3 km/h
C
4 km/h
D
5 km/h
Correct Answer:
A. 2 km/h
Explanation:
Upstream speed = 24/6 = 4 km/h. Downstream speed = 24/3 = 8 km/h. Current = (8-4)/2 = 2 km/h.
