Question

A boat in still water is 32 mph. If the boat travels 72 miles upstream in the same time that it takes to travel 120 miles downstream, find the speed of the current.

Answer 1

dup= 72 miles
ddown= 120 miles
v= riverspeed
rup= 32mph - v
rdown= 32mph + v
t both ways= t

d=r*t
d/r=t

t=ddown/rdown
t=dup/rup

dup/rup = ddown/rdown

(72)/(32-v)=(120)/(32+v)
3840-120v=2304+72v
1536=192v
v=8