Boats and streams: speed of the stream from downstream and upstream data

This type of question, asked 5 times: CDS 2 2016, CDS 2 2017, CDS 2 2021, CDS 1 2023, CDS 2 2026. All 5 questions below, oldest first.

Try each one first, then open its answer.

Question 1
CDS 2 2016
26 $A person can row downstream 20 km in 2 hours and upstream 4 km in 2 hours. What is the speed of the current ?$
Tap an option to check your answer.
Question 2
CDS 2 2017
45 $A man rows down a river 18 km in 4 hours with the stream and returns in 10 hours. Consider the following statements : 1. The speed of the man against the stream is 1.8 km/hr. 2. The speed of the man in still water is 3.15 km/hr. 3. The speed of the stream is 1.35 km/hr. Which of the above statements are correct ?$
Tap an option to check your answer.
Question 3
CDS 2 2021
33 $\frac{9}{2}$
Tap an option to check your answer.
Question 4
CDS 1 2023
40 $The speed of a boat in still water is 15 km/hr. If it can travel 42 km downstream and 28 km upstream in the same time, then what is the speed of the stream ?$
Tap an option to check your answer.
Question 5
CDS 2 2026
24 $A boatman can row to a place (Y) at a distance of 24 km from the starting point (X) and back in 14 hours. If he can row 4 km with the stream in the same time as 3 km against it, what is the speed of the stream ?$
Tap an option to check your answer.

Question 1