SOLUTION: A family takes a weekend trip to the lake. On the trip to the lake the road is dry, but on the trip home the road is slippery, so their speed home is only half as fast as their spe

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A family takes a weekend trip to the lake. On the trip to the lake the road is dry, but on the trip home the road is slippery, so their speed home is only half as fast as their spe      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1121067: A family takes a weekend trip to the lake. On the trip to the lake the road is dry, but on the trip home the road is slippery, so their speed home is only half as fast as their speed to the lake. The trip is 60 miles each way and the round trip takes 3 hours. What is the speed of the at on the dry road?
Found 2 solutions by htmentor, josgarithmetic:
Answer by htmentor(1343) About Me  (Show Source):
You can put this solution on YOUR website!
Let the speed home = s
Then the speed to the lake is 2s
The round trip time is 3 hours and each leg of the trip is 60 miles
Therefore we can express the time as t = t1 + t2 = 60/2s + 60/s = 3
Solving for s gives 180/2s = 3, s = 30
The speed on dry road is 2*30 = 60 mph

Answer by josgarithmetic(39615) About Me  (Show Source):
You can put this solution on YOUR website!
                       SPEED        TIME        DISTANCE

Dry-going              r            60%2Fr         60

Slippery-return        r%2F2          60%2F%28r%2F2%29       60

TOTAL                                 3

highlight_green%2860%2Fr%2B120%2Fr=3%29
Simplify and solve this equation.
-
180%2Fr=3

r%2F180=1%2F3

highlight%28r=60%29