If you look at Figure 13-3, you will see that the total distance is thesum
of the individual distances each car went, since each is going in the opposite
direction: 2xþ2(xþ10)¼160.
IMPLEMENTATION: Solve the equation forx:
2 xþ 2 ðxþ 10 Þ¼ 160
2 xþ 2 xþ 20 ¼ 160
4 xþ 20 ¼ 160
4 xþ 20 20 ¼ 160 20
4 x¼ 140
41 x
41
¼
140
4
x¼35 miles per hour
xþ 10 ¼ 35 þ 10 ¼45 miles per hour
Hence the slower automobile was traveling at 35 miles per hour and the
faster automobile was traveling at 45 miles per hour.
EVALUATION: We can find the distance each automobile traveled and then
see if the sum is 160 miles.
Automobile 1: D¼RT
D¼ 35 2 ¼70 miles
Automobile 2: D¼RT
D¼ 45 2 ¼90 miles
Hence, 70þ 90 ¼160 miles.
Try These
- Two people leave from two towns that are 195 miles apart at the same
time and travel along the same road toward each other. The first
136 LESSON 13 Solving Distance Problems