Question

A motor boat whose speed is 15km/hr in still water goes 30 km downstream and
comes back in a total of 4 hours 30 minutes. Determine the speed of the stream.​

Answer 1

Answer:

S OF BOAT =15KM/HR

STREAM SPEED =X

UPSTREAM S = 15-X KM /HR

DOWNSTREAM =15+X KM/HR

TIME TAKEN IN UPSTREAM= D/S

T1=30/15-X

TIME OF DOWNSTREAM=D/S

=30/15+X

NOW 30/15-X+30/15+X=4 30/60

[30(15+X)+30(15-X)] / (15-X) 15+X)=4 1/2

[450+X+450-X]/225+15X-15X-XSQUARE=9/2

900*2=9(225-X SQUARE)

1800-2025= -9X SQUARE

-225/9= -X SQUARE

X= ROOT 225/9

X=15/3

X=5