While driving from A-ville to B-town, Harriet drove at a constant speed of 90 kilometers per hour.
While driving from A-ville to B-town, Harriet drove at a constant speed of 90 kilometers per hour. Upon arriving in B-town, Harriet immediately turned and drove back to A-ville at a constant speed of 160 kilometers per hour. If the entire trip took 5 hours, how many minutes did it take Harriet to drive from A-ville to B-town?
Answer/Solution
192
Steps/Work
5hr = 300min.
If harriet spend equal hrs on each leg she will spend 150min on each. Since speed A-B is less than speed B-A and distance on each leg is the same, time spent on A-B is more than 150min, which mean we can eliminate ans. A, B and C.
Now let plug in ans. D or E and verify which one give same distance on each leg.
D. t= 162min
* leg A-B ---> d = 90.192/60 = 17280/60
* leg B-A ----> d = 160*108/60 = 17280/60
so the correct ans. isE
If harriet spend equal hrs on each leg she will spend 150min on each. Since speed A-B is less than speed B-A and distance on each leg is the same, time spent on A-B is more than 150min, which mean we can eliminate ans. A, B and C.
Now let plug in ans. D or E and verify which one give same distance on each leg.
D. t= 162min
* leg A-B ---> d = 90.192/60 = 17280/60
* leg B-A ----> d = 160*108/60 = 17280/60
so the correct ans. isE