Question

A boat is sent across a river with a velocity of $8km/h$. If the resultant velocity of boat is $10km/h$, then velocity of river is

• A. 10 km/h
• B. 8 km/h
• C. 6 km/h
• D. 4 km/h

Answer 1

Answer: (C)

Given $AB=$ velocity of boat $=8km/h$
$AC=$ Resultant velocity of boat $=10km/h$

$\therefore BC=$ Velocity of river $=\sqrt{A{C}^2-A{B}^2}$
$=\sqrt{(10{)}^2-(8{)}^2}=6km/h$