Question

Find the speed of the boat in still water, if a boat covers a certain distance upstream in 2 hours, while it comes back in 1`1/2` hours. If the speed of the stream be 3 kmph.

Answer 1

Answer:

Explanation:

Hey,

we also know that s is a constant

we know that speed=distance /time

                        v= s/t

upstream        

                        v-3=s/2*60*60

cross multiplying

s=7200v-21600

downstream

                        v+3=s/1.5*60*60

cross multiplying

s=5400v-16200

s=s

7200v-21600 =5400v-16200

1800v-37800=0

v=37800/1800

v=21

so speed of the boat in still water is 21 km/hr