Question

A child can row 12 meters in a swimming pool in 3 minutes. In how much time can he cover a distance of 100 meters against the stream in a river if speed of the stream is 1.5 meters per minute? (Water in the swimming pool is considered as still water)


20 mins


30 mins


40 mins


28 mins




​

Answer 1

Answer:

Here V  

R

​  

=     velocity of river

V  

M

​  

=       velocity of man in still water  = 2m/s (given)

from figure it is clear that

sinθ=  

V  

M

​  

 

V  

R

​  

 

​  

,              where θ=60          degree

⟹V  

R

​  

=  

3

​  

m/s

from figure it is evident that

V  

M

​  

cosθ×t=1000m

⟹t=1000                   s    

Step-by-step explanation: