Problem Solving

AbeNeedsAnswers wrote:Abdul, Barb, and Carlos all live on the same straight road, on which their school is also located. The school is halfway between Abdul's house and Barb's house. Barb's house is halfway between the school and Carlos's house. If the school is 4 miles from Carlos's house, how many miles is Abdul's house from Carlos's house?
A. 1 1/3
B. 2
C. 4
D. 6
E. 8

D

The school is halfway between Abdul's house and Barb's house.
Sketch it to get: A--------S--------B
Aside: The distances between A and S and between S and B are EQUAL


Barb's house is halfway between the school and Carlos's house.
Add Carlos's house to drawing: A--------S--------B--------C
Aside: All 3 distances are EQUAL

If the school is 4 miles from Carlos's house...
A--------S--------B--------C
So, the two RED distances add to 4 miles
Since those two distances are EQUAL, each distance must equal 2 miles.
That is: A----2miles----S----2miles----B----2miles----C

...how many miles is Abdul's house from Carlos's house?
The distance = 6 miles

Answer: D

Cheers,
Brent

AbeNeedsAnswers wrote:Abdul, Barb, and Carlos all live on the same straight road, on which their school is also located. The school is halfway between Abdul's house and Barb's house. Barb's house is halfway between the school and Carlos's house. If the school is 4 miles from Carlos's house, how many miles is Abdul's house from Carlos's house?
A. 1 1/3
B. 2
C. 4
D. 6
E. 8

D

Since the school is 4 miles from Carlos's house, and Barb's house is halfway between the school and Carlos's house, Barb's house is 2 miles from the school.

Since the school is halfway between Abdul's house and Barb's house, the school is 2 miles from Abdul's house.

Thus, Abdul's house is 6 miles from Carlos's house.

Answer: D

Hi All,

We're told that Abdul, Barb, and Carlos all live on the same straight road, on which their school is also located, the school is HALFWAY between Abdul's house and Barb's house and Barb's house is HALFWAY between the school and Carlos's house. We're asked - if the school is 4 miles from Carlos's house, then how many miles is Abdul's house from Carlos's house.

You might find that a drawing can help you to keep all of this information properly organized. Even without a drawing though, you should recognize that that the word "HALFWAY" shows up repeatedly in this prompt, so with some basic Addition and note-taking, you can answer this question without too much trouble.

We're told that....
1) The distance between the School and Carlos's house = 4 miles
2) Barb's house is HALFWAY between the School and Carlo's house....
.... thus, it's 2 miles from Barb's house to the School and 2 miles from Barb's house to Carlos' house.
3) The School is HALFWAY between Abdul's house and Barb's house....
.... since we know Barb's house is 2 miles from the School, Abdul's house must ALSO be 2 miles from the School (on the 'other side' of the School).

Thus, the distance from Abdul's house to the School is 2 miles and the distance from the School to Carlos's house is another 4 miles.
Total = 2 miles + 4 miles = 6 miles.

Final Answer: D

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