A person can row 8 km/h in still water. He finds that it takes him thrice as long to row upstream as to row downstream. Find the speed of the current. MCQ with Answer and Explanation

A person can row 8 km/h in still water. He finds that it takes him thrice as long to row upstream as to row downstream. Find the speed of the current.
A. 4 km/h
B. 3 km/h
C. 5 km/h
D. 6 km/h
Answer: Option A
Solution (By JKSSB Mock Tests)
Let current speed be c. Upstream speed = 8 - c, Downstream speed = 8 + c. Given: 3 * (8 - c) = 8 + c => 24 - 3c = 8 + c => 4c = 16 => c = 4 km/h.

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Practice More Time Speed and Distance Questions

Question #1
A passenger train 100 meters long clears a line worker tracking on the ballast track in 5 seconds flat when both move along the identical direction. If the line worker walks at 8 km/h, find the train speed.
A. 88 km/h
B. 84 km/h
C. 80 km/h
D. 76 km/h

Correct Answer: Option C


Explanation:
Relative tracking speed = 100 / 5 = 20 m/s = 20 * (18/5) = 72 km/h. In identical directions, Relative Speed = Speed of train - Speed of worker => 72 = Speed of train - 8 => Speed of train = 80 km/h.

This question belongs to: Maths Time Speed and Distance
Question #2
A man rows downstream 40 km in 4 hours and upstream 24 km in 4 hours. What is the speed of the stream?
A. 4 km/h
B. 2 km/h
C. 1 km/h
D. 3 km/h

Correct Answer: Option B


Explanation:
Downstream speed = 40 / 4 = 10 km/h. Upstream speed = 24 / 4 = 6 km/h. Speed of stream = (Downstream speed - Upstream speed) / 2 = (10 - 6) / 2 = 2 km/h.

This question belongs to: Maths Time Speed and Distance
Question #3
A sedan tracks from location M to N at 50 km/h and manages the return tract to M at 70 km/h. What is the average speed recorded across the round journey?
A. 61.25 km/h
B. 56.50 km/h
C. 58.33 km/h
D. 60.00 km/h

Correct Answer: Option C


Explanation:
Average Speed across course = 2xy / (x + y) = (2 * 50 * 70) / (50 + 70) = 7000 / 120 = 58.33 km/h.

This question belongs to: Maths Time Speed and Distance