BTGmoderatorDC wrote: ↑Tue Sep 28, 2021 7:37 pm
A committee is to be created from some employees at Bongo Industrials. The committee must include exactly 3 senior executives and 4 junior executives. If 5 senior executives and 6 junior executives are available for the committee, how many different committees are possible?
A. 10
B. 15
C. 25
D. 60
E. 150
OA
E
Source: Princeton Review
Take the task of creating the committee and break it into
stages.
Stage 1: Select 3 senior executives to be on the committee
Since the order in which we select the 3 senior executives does not matter, we can use combinations.
We can select 3 senior executives from 5 senior executives in 5C3 ways (10 ways)
So, we can complete stage 1 in
10 ways
Stage 2: Select 4 junior executives to be on the committee
Since the order in which we select the 4 junior executives does not matter, we can use combinations.
We can select 4 junior executives from 6 junior executives in 6C4 ways (15 ways)
So, we can complete stage 2 in
15 ways
By the Fundamental Counting Principle (FCP), we can complete the 2 stages (and thus create the committee) in
(10)(15) ways (= 150 ways)
Answer: E
Note: the FCP can be used to solve the MAJORITY of counting questions on the GMAT. For more information about the FCP, watch this video:
https://www.gmatprepnow.com/module/gmat- ... /video/775
You can also watch a demonstration of the FCP in action:
https://www.gmatprepnow.com/module/gmat ... /video/776
Then you can try solving the following questions:
EASY
-
https://www.beatthegmat.com/what-should- ... 67256.html
-
https://www.beatthegmat.com/counting-pro ... 44302.html
-
https://www.beatthegmat.com/picking-a-5- ... 73110.html
-
https://www.beatthegmat.com/permutation- ... 57412.html
-
https://www.beatthegmat.com/simple-one-t270061.html
MEDIUM
-
https://www.beatthegmat.com/combinatoric ... 73194.html
-
https://www.beatthegmat.com/arabian-hors ... 50703.html
-
https://www.beatthegmat.com/sub-sets-pro ... 73337.html
-
https://www.beatthegmat.com/combinatoric ... 73180.html
-
https://www.beatthegmat.com/digits-numbers-t270127.html
-
https://www.beatthegmat.com/doubt-on-sep ... 71047.html
-
https://www.beatthegmat.com/combinatoric ... 67079.html
DIFFICULT
-
https://www.beatthegmat.com/wonderful-p- ... 71001.html
-
https://www.beatthegmat.com/permutation- ... 73915.html
-
https://www.beatthegmat.com/permutation-t122873.html
-
https://www.beatthegmat.com/no-two-ladie ... 75661.html
-
https://www.beatthegmat.com/combinations-t123249.html
Cheers,
Brent