Bunuel wrote:

Carla can drive from her home to the mall by one of the two possible routes. If she must also return by one of these routes, what is the distance of the shorter route ?

(1) When she drives from her home to the mall by the shorter route and returns by the longer route, she drives a total of 35 kilometers.

(2) When she drives both ways, from her home to the mall and back, by the shorter route, she drives a total of 30 kilometers.

We can let L = the distance of the longer route and S = the distance of the shorter route. We need to determine the value of S.

Statement One Alone:When she drives from her home to the mall by the shorter route and returns by the longer route, she drives a total of 35 kilometers.

Let’s let S = the one-way distance via the short route and L = the one-way distance via the long route. Using the information in statement one, we can create the following equation:

S + L = 35

However, we cannot determine S. Statement one alone is not sufficient to answer the question.

Statement Two Alone:When she drives both ways, from her home to the mall and back, by the shorter route, she drives a total of 30 kilometers.

Using the information in statement two, we can create the following equation:

S + S = 30

2S = 30

S = 15

Statement two alone is sufficient to answer the question.

Answer: B

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