A Drive Out of TownMath brain teasers require computations to solve.
Abe Drivers has to drive 200 km once a week to pick up his deliveries from the post office. He then quickly drives home to open them up.
One week, he left off and, expecting something, drove at 110 km/h. When he reached the post office, there was nothing, so he drove home at the same speed, feeling disappointed.
The next week, he drove at 105 km/h and when he reached the post office, he was able to pick up a big package. When he drove home, he was travelling at 115 km/h.
His daughter, Raine, came down and, being the most curious of girls and the most brilliant of mathematicians, asked her dad how fast he drove for both weeks. When he answered, he said that they took the same time. But Raine disagreed.
Who was correct? Raine or Abe? If Abe, how long did it take him to drive there and back? If Raine, how many hours/minutes/seconds was there in the difference?
AnswerRaine was right.
Drive A: 200km. 110km/h. 200/110=1.818 [1.818*2= 3.636]
Drive B: 200km. 105km/h. 200/105=1.905 115km/h. 200/115=1.739 [1.905+1.739= 3.644]
Converting it, A takes 3h 38m 10s and B takes 3h 38m 38s. Therefore, Drive A took 28 fewer seconds than Drive B.
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