Question

A swimmer covers a distance of 42km downstream and 18 km upstream. If in each case he takes 3 hours, find the speed of the stream.

Answer 1

$\boxed{\begin{minipage}{7 cm} Fundamental Trigonometric Identities \\ \\ \sin^2\theta+\cos^2\theta=1 \\ \\ 1+\tan^2\theta \\ \\ 1+\cot^2\theta = \text{cosec}^2 \, \theta \end{minipage}}$