Position Selection

[vinay1983]

A certain university will select I of 7 candidates eligible to fill a position in the mathematics department and 2 of 10 candidates eligible to f ll 2 identical positions in the computer science department. lf none of the candidates is eligible for a position in both departments, how many different sets of 3 candidates are there to f ll the 3 positions?


(A) 42
(B) 70
(C) 140
(D) 165
(E) 315

My query is what portion does this part"lf none of the candidates is eligible for a position in both departments, how many different sets of 3 candidates are there to fill the 3 positions? play in determining the question. What does it mean.Though I got the correct answer, yet I am wondering what is the purpose of that sentence and what it means?

OA: E

[ganeshrkamath]

A certain university will select I of 7 candidates eligible to fill a position in the mathematics department and 2 of 10 candidates eligible to f ll 2 identical positions in the computer science department. lf none of the candidates is eligible for a position in both departments, how many different sets of 3 candidates are there to f ll the 3 positions?


(A) 42
(B) 70
(C) 140
(D) 165
(E) 315

My query is what portion does this part"lf none of the candidates is eligible for a position in both departments, how many different sets of 3 candidates are there to fill the 3 positions? play in determining the question. What does it mean.Though I got the correct answer, yet I am wondering what is the purpose of that sentence and what it means?

OA: E

Choose 1 out of 7 : 7C1 = 7
Choose 2 out of 10 : 10C2 = 10*9/2 = 45

Total number of combinations = 7*45 = 315

Choose D

To answer your question, the above answer would not hold if a person was eligible for both the departments. The number of combinations would then increase.

Cheers

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Hi ganeshrkamath,

GMAT questions are always carefully worded, so that the question (whether Quant or Verbal) can't be argued as unfair or misleading. This wording also affects HOW you're supposed to do the "math" that's involved, so you have to pay careful attention to what is stated. This also serves another purpose: it's a measure of the strength of your attention to detail. If you can't pay attention to the details, then you don't deserve a high score.

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