Question 321989: a boat can go 9 km. downstream in 45 mins. & return in an hour. find the speed of the boat in still water and the speed of the current. Answer by mananth(16949) (Show Source):
You can put this solution on YOUR website! a boat can go 9 km. downstream in 45 mins.
return 9 km in an hour.
let speed of boat in still water be x mph
speed of current be y mph
..
9/ x+y= 3/4
36=3(x+y)
12 = x+y......... equation 1
9/x-y= 1
x-y=9.............equation 2
Add the two equations
x+y+x-y=12+9
2x=21
x=10.5 mph
..
x-y=9
plug the value of x
10.5-y=9
y=1.5 mph
