A person row a distance of 16 km downstream in 2 hours and the same distance upstream in 4 hours. What is the speed of the boat in still water? MCQ with Answer and Explanation

A person row a distance of 16 km downstream in 2 hours and the same distance upstream in 4 hours. What is the speed of the boat in still water?
A. 5 km/h
B. 7 km/h
C. 6 km/h
D. 8 km/h
Answer: Option C
Solution (By JKSSB Mock Tests)
Downstream speed = 16 / 2 = 8 km/h. Upstream speed = 16 / 4 = 4 km/h. Speed in still water = (8 + 4) / 2 = 6 km/h.

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Practice More Time Speed and Distance Questions

Question #1
A car covers three successive 10 km stretches at speeds of 20 km/h, 30 km/h and 60 km/h respectively. Find its average speed.
A. 30 km/h
B. 32 km/h
C. 28 km/h
D. 35 km/h

Correct Answer: Option A


Explanation:
Total distance = 3 * 10 = 30 km. Total time taken = 10/20 + 10/30 + 10/60 = 1/2 + 1/3 + 1/6 = 1 hour. Average speed = 30 / 1 = 30 km/h.

This question belongs to: Maths Time Speed and Distance
Question #2
A truck covers 60 km at 30 km/h and then another 100 km at 50 km/h. Find the overall average speed for the full transit.
A. 38 km/h
B. 42 km/h
C. 45 km/h
D. 40 km/h

Correct Answer: Option D


Explanation:
Total distance = 60 + 100 = 160 km. Time for first leg = 60 / 30 = 2 hours. Time for second leg = 100 / 50 = 2 hours. Total time = 4 hours. Average speed = 160 / 4 = 40 km/h.

This question belongs to: Maths Time Speed and Distance
Question #3
A person walks from home to school at 5 km/h and arrives 6 minutes late. If he runs at 6 km/h, he arrives 4 minutes early. Find the distance.
A. 5.0 km
B. 6.0 km
C. 4.5 km
D. 5.5 km

Correct Answer: Option A


Explanation:
Time difference = 6 - (-4) = 10 minutes = 10/60 = 1/6 hours. Let distance be d. d / 5 - d / 6 = 1/6 => d / 30 = 1/6 => d = 5 km.

This question belongs to: Maths Time Speed and Distance