Question

It takes Darline 20 minutes to drive to work in light traffic. To come home when there is heavy traffic, it takes her 36 minutes. Her speed in light traffic is 24 miles per hour faster than her speed in heavy traffic. Find her speed in light traffic and in heavy traffic.

Answer 1

Her speed in heavy traffic = 30 miles per hr

Her speed on light traffic = 24 + 30 = 54 miles per hr

Explanation:

It takes Darline 20 minutes to drive to work in light traffic. To come home when there is heavy traffic she uses 36 minutes.

The distance covered is the same.

Light traffic

speed = distance/time

speed = distance/20

speed = 24 + y

24 + y = distance/20

cross multiply

distance = (24 + y) × 20

distance = 480 + 20y

Heavy traffic

speed = distance/time

speed = distance/36

let speed = y

36y = distance

480 + 20y = 36y

480 = 36y - 20y

480 = 16y

y = 480/16

y = 30

Her speed in heavy traffic = 30 miles per hr

Her speed on light traffic = 24 + 30 = 54 miles per hr