Problema Solution
Two friends decide to meet in Chicago to attend a Cub's baseball game. Rob travels 171 miles in the same time that Carl travels 156 miles. Rob's trip uses more interstate highways and he can average 5 mph more than Carl. What is Rob's average speed?
Answer provided by our tutors
Let
v = Carl's average speed, v>=0
v + 5 = Rob's average
d1 = 156 mi the distance Carl travels
d2 = 171 mi the distance Rob travels
Since speed = distance/time follows time = distance/speed and since they traveled the same time we have:
d1/v = d2/(v + 5)
156/v = 171/(v + 5)
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click here to see the equation solved for v
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v = 52 mph
v + 5 = 52 + 5 = 57 mph
Rob's average speed is 57 mph.