A man rows upstream 13 km and downstream 28 km, taking 5 hours each time. Find the speed of the stream. MCQ with Answer and Explanation

A man rows upstream 13 km and downstream 28 km, taking 5 hours each time. Find the speed of the stream.
A. 2 km/h
B. 1.5 km/h
C. 2.5 km/h
D. 3 km/h
Answer: Option B
Solution (By JKSSB Mock Tests)
Upstream speed = 13 / 5 = 2.6 km/h. Downstream speed = 28 / 5 = 5.6 km/h. Speed of stream = (Downstream speed - Upstream speed) / 2 = (5.6 - 2.6) / 2 = 3 / 2 = 1.5 km/h.

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Practice More Time Speed and Distance Questions

Question #1
A car covers a distance of 150 km in 2 hours 30 minutes. What should be its speed to cover the same distance in 2 hours?
A. 70 km/h
B. 80 km/h
C. 85 km/h
D. 75 km/h

Correct Answer: Option D


Explanation:
Required speed = Distance / Time = 150 / 2 = 75 km/h.

This question belongs to: Maths Time Speed and Distance
Question #2
A car covered a distance of 300 km at a uniform speed. If the baseline speed is lowered by 10 km/h, the trip duration spikes by 1 hour. Find the original speed.
A. 65 km/h
B. 60 km/h
C. 70 km/h
D. 55 km/h

Correct Answer: Option B


Explanation:
Let original speed be s. 300 / (s - 10) - 300 / s = 1 => 300(10) = s(s - 10) => 3000 = s(s - 10). Solving s^2 - 10s - 3000 = 0 yields (s - 60)(s + 50) = 0. Since speed must be positive, s = 60 km/h.

This question belongs to: Maths Time Speed and Distance
Question #3
A man rows a boat 30 km downstream in 3 hours and returns upstream in 6 hours. Find the speed of the stream.
A. 2.0 km/h
B. 3.5 km/h
C. 3.0 km/h
D. 2.5 km/h

Correct Answer: Option D


Explanation:
Downstream speed = 30 / 3 = 10 km/h. Upstream speed = 30 / 6 = 5 km/h. Speed of stream = (10 - 5) / 2 = 2.5 km/h.

This question belongs to: Maths Time Speed and Distance