Question

Two skaters race in different directions. The first skater travels at 18 mph and the second travels at 23 mph. How long will it be before they are 123 miles apart?

Answer 1

first skater:

d=rt
d1=18t

second skater

d=rt
d2=23t

Add the distances to get

d1+d2 =18t+23t =41t

So their total distance apart at time t is 41t

We want this distance to be 123 miles, so


41t = 123
t = 123/41
t = 3

So it will take 3 hours for them to be 123 miles apart.