A boat can row 15 km/h in still water. If the river current flows at 5 km/h, find the total time taken by the boat to row 40 km upstream. MCQ with Answer and Explanation

A boat can row 15 km/h in still water. If the river current flows at 5 km/h, find the total time taken by the boat to row 40 km upstream.

A. 5 hours

B. 4 hours

C. 3 hours

D. 6 hours

Answer: Option B

Upstream speed = 15 - 5 = 10 km/h. Time taken = Distance / Upstream speed = 40 / 10 = 4 hours.

This question belongs to: Maths Time Speed and Distance

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Question #1 Report Error

A boat can row 10 km/h in still water. If the river velocity is 2 km/h, find the distance covered downstream by the boat in 30 minutes.

A. 5 km

B. 7 km

C. 6 km

D. 8 km

Correct Answer: Option C

Explanation:
Downstream speed = 10 + 2 = 12 km/h. Time = 30 minutes = 0.5 hour. Distance covered = Speed * Time = 12 * 0.5 = 6 km.

This question belongs to: Maths Time Speed and Distance

Question #2 Report Error

Walking at 4/5 of his normal speed, a man is 12 minutes late. What is his usual time to cover the journey?

A. 60 minutes

B. 40 minutes

C. 48 minutes

D. 36 minutes

Correct Answer: Option C

Explanation:
New Time = 5/4 of usual time. Difference = 1/4 * Usual Time = 12 minutes => Usual Time = 48 minutes.

This question belongs to: Maths Time Speed and Distance

Question #3 Report Error

A boat can row 15 km/h in still water. If the river current flows at 3 km/h, find the distance covered by the boat downstream in 20 minutes.

A. 7 km

B. 5 km

C. 8 km

D. 6 km

Correct Answer: Option D

Explanation:
Downstream speed = 15 + 3 = 18 km/h. Time = 20 minutes = 20/60 = 1/3 hour. Distance covered = Speed * Time = 18 * (1/3) = 6 km.

This question belongs to: Maths Time Speed and Distance