Speed/current word problem

Question

Len is planning a three hour trip down the river and back to his starting point. He can paddle in still water at 3mi/h and the current is 2mi/hr. How much time can he spend going downstream? How far downstream can he travel?

Answer 1

distance=rate*time

d=(3+2)t downstream

d=(3-2)(3-t) upstream

simplify both equations

d=5t

d=(1)(3-t)

the right sides are both equal to d so set them equal to each other

5t=3-t

5t+t=3

6t=3

t=3/6=1/2 hour going downstream

d=(5)(1/2)

d=2.5 miles traveled downstream