Carcass wrote:

Car X and Car Y traveled the same 80-mile route. If Car X took 2 hours and Car Y traveled at an average speed that was 50 percent faster than the average speed of Car X, how many hours did it take Car Y to travel the route?

(A) 2/3

(B) 1

(C) 4/3

(D) 8/5

(E) 3

There's a

nice rule we can use here.

To set up the rule, recognize that if Y travels

2 times as fast as X, then Y's travel time will be

1/2 of X's.

Similarly, if Y travels

3 times as fast as X, then Y's travel time will be

1/3 of X's.

Or if Y travels

1/4 as fast as X, then Y's travel time will be

4 times X's travel time.

In general,

if Y travels a/b times as fast as X, then Y's travel time will be b/a of X's travel time.So, if Y's speed is 50%

more than X's speed, we can say that Y travels 1.5 times as fast as X.

In other words, if Y travels

3/2 times as fast as X, which means Y's travel time will be

2/3 that of X's travel time.

Since X's travel time is 2 hours, Y's travel time will be (

2/3)(2) = 4/3 = 1 1/3

Answer: C

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

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