Question

Consider a boat which moves at the speed of 6 km/hr. If the water runs at the speed of about 4 km/hr, then the boat requires 3 hours to reach a certain place and return. Calculate the distance between that place and boat's initial position.

Answer 1

Explanation:

Distance between two places = [t(x² – y²)]/2x km/h

Given: Speed of boat (x) = 6 km/hr

Speed of water (y) = 4 km/hr

Time taken by the boat to go & return back = t = 3 hrs

To find the distance between the place & initial position of boat (i.e. between two places), we have

D = [t(x² – y²)]/2x

D = [3 x (6² – 4²)]/2(6)

= [3 x (20)] /12

= 60/12

= 5 km/hr

Answer 2

Answer:

5

Explanation:

speed of boat in still water  x=6

speed of stream                   y=4

Tu +Td = 3

d /2 + d/10 =3

by calculating d=5