SOLUTION: A motorboat takes 4 hours to travel 256 mi going upstream. The return trip takes 2 hours going downstream. What is the rate of the boat in still water and what is the rate of the c

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Question 288541: A motorboat takes 4 hours to travel 256 mi going upstream. The return trip takes 2 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?
Answer by mananth(16946) About Me  (Show Source):
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A motorboat takes 4 hours to travel 256 mi going upstream. The return trip takes 2 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?
let speed of the boat in still water be x
let the speed of the current be y
upstream speed of boat is x-y
distance is 256
time is 4 hours
256 / x-y =4
Down stream
speed of boat = x+y
distance = 256
256/ x+y = 2
4x-4y=256------------1
2x+2y=256------------2
multiply eq 2 by 2
4x+4y=512-----------3
Add eq 1 & 3
4x-4y+4x+4y=512+512
8x=1024
x= 1024/8
=128 mph
plug the value of x in eq1
we get y=64mph speed of the current