tricky speed problem

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tricky speed problem

by Redhorsep » Sun Aug 14, 2011 8:46 am
A sports car and a truck traveled distances of 120 and 100 miles, respectively, in a certain period of time. What was the average speed of the truck?

1. It took the car 30 minutes to travel half of the distance
2. The average speed of the truck was 10 miles less per hour less than the average speed of the car


Thanks for your help!
Source: — Data Sufficiency |

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by GmatKiss » Sun Aug 14, 2011 10:17 am
IMO:E

1)No information about truck's speed/ car's speed. Not sufficient
2)We don't know the speed of car! Not sufficient

1+2, We know only the speed of car for 50 miles and that the truck's avg. speed is 10 miles less per hour less than the average speed of the car ( Not sufficient)