Two ships and are apart on a line running south to north

PHYSICS · Subjective · ISC · Physics · Kinematics · Kinematics

Problem

Two ships

A

and

B

are

10\,\text{km}

apart on a line running south to north. Ship

A

, farther north, is steaming west at

20\,\text{km h}^{-1}

and ship

B

is steaming north at

20\,\text{km h}^{-1}

. What is their distance of closest approach and how long do they take to reach it?