# Discussion of Question with ID = 057 under Boats-and-Streams

## This is the discussion forum for this question. If you find any mistakes in the solution, or if you have a better solution, then this is the right place to discuss. A healthy discussion helps all of us, so you are requested to be polite and soft, even if you disagree with the views of others. The question and its current solution has also been given on this page.

### Question

The speed of a boat in still water, the upstream speed of the boat and the downstream speed of the boat form an A.P.(Arithmetic Progression) whose middle term is \${5/8}\$. What is the speed of the boat in still water?

A

\${5/8}\$ units.

B

\$1{6/7}\$ units.

C

\$2{1/10}\$ units.

D

\$2{9/10}\$ units.

Soln.
Ans: a

Let the speed of the boat in still water be u and the speed of the stream be v. The three speeds are u - v, u and u + v. They are in an A.P. with a common difference equal to v, and u as its middle term. Since u is also the speed of the boat in still water, the required answer is: \${5/8}\$.