SOLUTION: Bob was driving home at an average speed of 40mph for 2 hours. How fast should he drive for the next 1 hour to have an average speed of 50mph

Question 1155855: Bob was driving home at an average speed of 40mph for 2 hours. How fast should he drive for the next 1 hour to have an average speed of 50mph
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52858) (Show Source): You can put this solution on YOUR website!
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If the average speed is 50 mph during the 3-hours trip, then the total distance is (2+1)*50 = 150 miles. In 2 hours, he just covered 2*40 = 80 miles. Hence, he should cover the rest 150-80 = 70 miles in the last, third hour. ANSWER. He should drive at 70 mph.

Answer by josgarithmetic(39626) (Show Source): You can put this solution on YOUR website!

SPEED TIME DISTANCE Was doing 40 2 40*2=80 Next hour r 1 r TOTALS 3 r+80

Want average speed , 50 mph.

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