The speed of a boat in still water is 10 km/h. If its speed downstream is 18 km/h, the distance travelled by the boat upstream in 5 hours is :
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 10 km
Let the speed of the stream be $x$ km/hr
Downstream speed = $10+x=18$
$⇒x=8km/hr$
Upstream speed = $10-8=2km/hr$
Distance = Speed × Time
$=2×5=10km$