Question 1040343

Raina drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 
12
 hours. When Raina drove home, there was no traffic and the trip only took 
8
 hours. If her average rate was 
20
 miles per hour faster on the trip home, how far away does Raina live from the mountains?
<pre>Let distance be D
Speed to mountains: {{{D/12}}}, and speed home = {{{D/8}}}
We then get the following SPEED equation: {{{D/12 = D/8 - 20}}}
2D = 3D - 480------- Multiplying by LCD, 24
2D – 3D = - 480
D, or distance = {{{(- 480)/(- 1)}}}, or {{{highlight_green(matrix(1,2, 480, miles))}}}