Question

A boat goes 30 km up stream and 44km down stream in 10 hours . In 13 hours it can go 40km up steam and 55 km in down stream determine the speed of the stream and that of boat in still water



pls with steps answer

Answer 1

stream of boat=x
stream of still Water y
1/x-y= a
1/x+y=b
(30/x-y)+(44/x+y)=10
30a+44b=10-----(1)
similarly,
40a+55b=13-----(2)

(1)*4= 120a+176b=40
(2)*3= 120a+165b=39
(-)
11b=1
b=1/11
that is x+y=11-----(3)
sub b value in (2)

40a+5=13
40a=8
a=1/5
x-y=5------(4)
add (3) and (4)
2x=16
x=8
x-y=5
8-y=5
y=3