Solving distance, rate ant time using system of linear equations

Question

A motorboat takes
4
hours to travel
128mi
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 1

speed of boat=x mph
speed of current=y mph

 

 

 

upstream speed = x-y

 

speed * time = distance

 (x-y) *  4      =128

 

  x-y   =  32  _________ eq 1

 

down stream speed = x+ y
(x+y)*2 = 128

 

x+ y = 64 ________eq 2

add both the equations
x-y+x+y=32 + 64
2x=96

x=48 mph. speed of boat

x-y=32
48-y=32
y=16 mph speed of current