Carcass wrote:

There are 5 doors to a lecture room. Two are red and the others are green. In how many ways can a lecturer enter the room and leave the room from different colored doors?

(A) 1

(B) 3

(C) 6

(D) 9

(E) 12

Scan the answer choices....

Since all the answer choices are small, we could also just

list and count the possible outcomesLet

A and

B be the 2 RED doors

Let

C,

D and

E be the 3 GREEN doors

So, the possible outcomes are:

ENTER through door

A, and EXIT through door

CENTER through door

A, and EXIT through door

DENTER through door

A, and EXIT through door

EENTER through door

B, and EXIT through door

CENTER through door

B, and EXIT through door

DENTER through door

B, and EXIT through door

EENTER through door

C, and EXIT through door

AENTER through door

C, and EXIT through door

BENTER through door

D, and EXIT through door

AENTER through door

D, and EXIT through door

BENTER through door

E, and EXIT through door

AENTER through door

E, and EXIT through door

BThere are 12 possible outcomes.

Answer: E

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

Sign up for my free GRE Question of the Day emails