Question 384366
boat speed x mph
current speed = y
...
upstream speed = x-y
downstream speed x+y
..
distance = 3 miles
..
t=d/r
..
3/(x-y)=3/5
cross multiply
3(x-y)15
/3
x-y =5.........................1
..
3/(x+y)=1/5
x+y =15.........................2
..
add 1 & 2
2x=20
/2
x= 10.

speed of boat in still water = 10 mph.
m.ananth@hotmail.ca