Showing 631–640 of 1,106 questions
A boat takes 3 hours to travel 72 km downstream and 6 hours to travel the same distance upstream. What is the speed of the current?
A
4 km/h
B
6 km/h
C
8 km/h
D
5 km/h
Correct Answer:
B. 6 km/h
Explanation:
Downstream speed = 72/3 = 24 km/h. Upstream speed = 72/6 = 12 km/h. Current = (24-12)/2 = 6 km/h
A sum becomes Rs. 14400 in 2 years at 20% per annum compound interest. What is the principal?
A
Rs. 10000
B
Rs. 12000
C
Rs. 15000
D
Rs. 18000
Correct Answer:
A. Rs. 10000
Explanation:
P(1.2)² = 14400. P × 1.44 = 14400. P = Rs. 10000
X can do a work in 12 days, Y can do it in 18 days. They work together for 3 days, then X leaves. In how many more days will Y complete the work?
A
10.5 days
B
9 days
C
11 days
D
12 days
Correct Answer:
A. 10.5 days
Explanation:
Work done in 3 days = 3(1/12 + 1/18) = 3(3/36 + 2/36) = 3 × 5/36 = 5/12. Remaining = 7/12. Y completes 7/12 in (7/12)/(1/18) = 7/12 × 18 = 10.5 days
If 15% of a number is 45, what is 40% of that number?
Explanation:
Number = 45 × 100/15 = 300. 40% of 300 = 300 × 40/100 = 120
A number increases by 25%, then decreases by 20%. What is the net percentage change?
Explanation:
Let number = 100. After 25% increase: 125. After 20% decrease on 125: 125 × 0.8 = 100. Net change = 0%
In a shop, the cost price of an item is Rs. 500. If it's sold at 35% profit, what is the selling price?
A
Rs. 675
B
Rs. 650
C
Rs. 700
D
Rs. 625
Correct Answer:
A. Rs. 675
Explanation:
SP = CP + Profit = 500 + (35% of 500) = 500 + 175 = Rs. 675
A can complete a task in 20 days. B can complete it in 30 days. If they work together, how many days will it take?
A
10 days
B
12 days
C
15 days
D
8 days
Correct Answer:
B. 12 days
Explanation:
A's work rate = 1/20, B's work rate = 1/30. Combined rate = 1/20 + 1/30 = 5/60 = 1/12. Time = 12 days
Pipe A fills a tank in 15 hours. Pipe B fills it in 10 hours. If both pipes are open, in how much time will the tank be filled?
A
5 hours
B
6 hours
C
7.5 hours
D
8 hours
Correct Answer:
B. 6 hours
Explanation:
Combined rate = 1/15 + 1/10 = 2/30 + 3/30 = 5/30 = 1/6. Time = 6 hours
A train travels at 60 km/h. How long will it take to cover 300 km?
A
4 hours
B
5 hours
C
6 hours
D
3 hours
Correct Answer:
B. 5 hours
Explanation:
Time = Distance/Speed = 300/60 = 5 hours
A boat travels downstream at 12 km/h and upstream at 8 km/h. 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:
Speed of current = (Downstream speed - Upstream speed)/2 = (12 - 8)/2 = 2 km/h
