Question

A swimmer's speed with the current is $12$ km/hr and the speed of the current is $5$ km/hr. The swimmer's speed against the current and speed in still water are

• A. $5$ and $12$ km/hr
• B. $2$ and $7$ km/hr
• C. $7$ and $2$ km/hr
• D. $3$ and $7$ km/hr

Answer 1

The correct option is B $2$ and $7$ km/hr

Swimmer's speed in still water
$=$ swimmer's speed with the current $-$ speed of the current
$=(12-5)$ km/hr
$=7$ km/hr
Now, swimmer's speed against the current
$=$ swimmer's speed in still water $-$ speed of the current
$=(7-5)$ km/hr
$=2$ km/hr