Question

Jim paddles from one shore of a lake three miles wide at 4 mph, and John paddles from the opposite shore at 5 mph. How long will they travel before they meet?

A. 1 hour, 24 minutes
B. 20 minutes
C. 3 hours
D. 27 minutes

Answer 1

The correct answer is B. 20 minutes

Answer 2

answer is B
d=sp
d=distance
s=speed
t=time
so
here is Jims equation
4t=d
John's equation
5t=3-d
we need to subtract d from 3 because their speeds are different so the distance will be different. Time stays the same.
5t=3-d
5t-3=-d
3-5t=d
now we can set the equation equal to each other
4t=d and 3-5t=d
4t=3-5t
9t=3
t=3/9=1/3
1/3 of an hour is 20 minutes
so the answer is B