SOLUTION: Danielle drives from her home to the store at an average speed of 40 miles per hour. She returns home along the same route at an average speed of 60 miles per hour. What is her ave
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Question 363355: Danielle drives from her home to the store at an average speed of 40 miles per hour. She returns home along the same route at an average speed of 60 miles per hour. What is her average speed, in miles per hour, for her entire trip? Answer by amoresroy(361) (Show Source):
You can put this solution on YOUR website! Let S = Speed
T = travel time
D = distance traveled
Given:
S1 = 40
S2 = 60
Ave S = Total distance traveled divided by total travel time
= 2D / ( T1 + T2)
= 2D / (D/40 + D/60)
= 120 * 2D / [120*(D/40) + 120*(D/60)]
= 240 D / (3D + 2D)
= 240/5
= 48 miles per hour
