Question

Two boats have speeds on still water as 5 m/s and 4 m/s. They are moving towards each other on a river which moves at 2 m/s. The fast boat is moving against the river current. Initially, they are 180 m apart. Find the time taken for them to meet. Please ignore the lengths of the boats.

• A. 20 seconds
• B. 22 seconds
• C. 24 seconds
• D. 25 seconds

Answer 1

The correct option is A 20 seconds

As the two boats are on the same river in opposite directions, the speed of the river current does NOT matter.

So, the relative speed of the two boats will be the sum of their respective speeds as they are moving towards each other.

So, the relative speed will be 9 m/s.

And the time taken = 180/9 = 20 sec

Hence, option (A) is the correct answer.