Question

A man's speed with the current is $15$ km/hr and the speed of the current is $2.5$ km/hr. The man's speed against the current is

• A. $8.5$ km/hr
• B. $9$ km/hr
• C. $2.5$ km/hr
• D. $10$ km/hr

Answer 1

The correct option is D $10$ km/hr

Man's speed in still water
$=$ man's speed with the current $-$ speed of the current
$=(15-2.5)$ km/hr
$=12.5$ km/hr
Now, man's speed against the current
$=$ man's speed in still water $-$ speed of the current
$=(12.5-2.5)$ km/hr
$=10$ km/hr