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# Number of studying Biology Number not studying biology Total

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Intern
Joined: 10 Oct 2008
Posts: 5
Number of studying Biology Number not studying biology Total [#permalink]

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10 Oct 2008, 11:59
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Number of studying Biology Number not studying biology Total

No. of boys 18 (total no. of boys are 18)

No. of girls

Total 26(total No.of studying biology students)

The table above shows the number of students in a certain high school class who are boys and the number of students in the class who are studying biology. What is the total number of students in the class?
(1) Of the boys in the class, 15 are studying biology.
(2) The number of girls in the class is twice the number of students in the class who are not studying biology.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Manager
Joined: 15 Dec 2008
Posts: 52
Schools: HBS(08) - Ding. HBS, Stanford, Kellogg, Tuck, Stern, all dings. Yale - Withdrew App. Emory Executive -- Accepted, Matriculated, Withdrewed (yes, I spelled it wrong on purpose). ROSS -- GO BLUE 2011.

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17 Mar 2009, 08:16
1
KUDOS
winter09 wrote:
Number of studying Biology Number not studying biology Total

No. of boys 18 (total no. of boys are 18)

No. of girls

Total 26(total No.of studying biology students)

The table above shows the number of students in a certain high school class who are boys and the number of students in the class who are studying biology. What is the total number of students in the class?
(1) Of the boys in the class, 15 are studying biology.
(2) The number of girls in the class is twice the number of students in the class who are not studying biology.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

I've attached a picture, here the explaination as well...

From the stem we know total bio students is 26, and total boys is 18.
Statement 1 tells us 15 boys are studying biology. 15 boys + X Girls = 26. so there are 11 girls. 15 boys in bio + X boys not in Bio = 18, so 3 boys not in bio.

I dont know enough to solve for students not in bio, or total girls, so insufficient.

Statement 2 tells us total girls is twice total not in bio. So total not in bio is X, which means total students = 26 + X. Total girls = 2X, so total students =2X+18
26+X=2X+18 -- I can solve for X, so Sufficient.
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Re: biology students   [#permalink] 17 Mar 2009, 08:16
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# Number of studying Biology Number not studying biology Total

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