Three friends, A, B and C have houses along a...

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

This topic has expert replies

Post new topic Post Reply

Previous Topic Next Topic

BTGmoderatorLU: Moderator; Posts: 2505; Joined: Sun Oct 15, 2017 1:50 pm; Followed by:6 members

Three friends, A, B and C have houses along a...

by BTGmoderatorLU » Thu Oct 26, 2017 6:10 am

Three friends, A, B and C have houses along a straight road, in that order. If all three want to meet up at one of their houses, what is the minimum combined distance they need to travel?

(1)The distance between A's house and B's house is 2 miles.
(2) The distance between A's house and C's house is 8 miles.

The OA is B.

I need help to solve this PS question. Can any expert explain it please? Thanks.

Quote

Source: Beat The GMAT — Problem Solving | Thu Oct 26, 2017 6:10 am

GMAT/MBA Expert

[email protected]: Elite Legendary Member; Posts: 10392; Joined: Sun Jun 23, 2013 6:38 pm; Location: Palo Alto, CA; Thanked: 2867 times; Followed by:511 members; GMAT Score:800

by [email protected] » Thu Oct 26, 2017 10:36 am

Hi LUANDATO,

We're told that three friends (A, B and C) have houses along a straight road in that order. We're asked for the minimum combined distance the 3 would need to travel to meet up at one of their houses. This question is actually more about 'logic' than 'math.'

To start, since the 3 will meet up at one of the houses, one of the three people won't have to travel at all (meaning that we have to think about how to minimize the distance that the other 2 people would have to travel. To that end, everyone should meet 'in the middle' (at person B's house).

1)The distance between A's house and B's house is 2 miles.

Fact 1 tells us how far A would have to travel (2 miles), but we don't know how far C would have to travel.
Fact 1 is INSUFFICIENT

2) The distance between A's house and C's house is 8 miles.

Fact 2 is a subtle piece of information, but it tells us how far those 2 people would have to travel in TOTAL. Regardless of where person B's house is, A and C would have to travel a TOTAL of 8 miles to get there.

For example, if house B was exactly 'in the middle', then both A and C would travel 4 miles.... for a total of 8 miles.
If house B was a bit closer to house A, and if A had to travel 3 miles to get to B, then person C would have to travel 5 miles to get to B's house... for a total of 8 miles. Thus, the answer to the questions ALWAYS 8 miles.
Fact 2 is SUFFICIENT

Final Answer: B

GMAT assassins aren't born, they're made,
Rich

Contact Rich at [email protected]