Question

A boat covers 32km upstream and 36km downstream in 7 hours. Also, it covers 40km
upstream and 48km downstream in 9 hours. Find the speed of the boat in still water and that
of the stream.

Answer 1

Answer:

refer to the pics u will understand!

Answer 2

Solution:-

Given:-

Speed of boat=10 km/h

Speed of stream=2 km/h

Let the speed of boat in still water=x km/hr and that in stream= y km/hr.

Condition |,

32/(x-y) + 36/(x+y) = 7 ---(i)

Condition ||,

40/(x-y) + 48/(x+y) = 9 ---(ii)

Taking 1/(x-y) =a and 1/(x+y)=b. we get,

32a + 36b =7 ---(iii) and 

40a + 48b= 9 ---(iv)

On solving (iii) & (iv), we get,

a=1/8 and b=1/12

According to our Assumption;

=) x-y=8

=) x = 8+y

putting ( x = 8 +y) in x+y=12. we get

=) 8 + y + y = 12

=) 2y = 4

=) y = 2

& x = 8+y

=) x = 8+2

=) x = 10

Hence,

x = 10 and y = 2.