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GRE Math Challenge #30-In the history class that consisted
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Updated on: 14 Mar 2018, 15:32
Updated on: 14 Mar 2018, 15:32
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66% (01:10) correct
33% (00:59) wrong based on 59 sessions
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In the history class that consisted of 30 students, the number of seniors was 3 more than twice the number of juniors, and 3/10 of the students were neither juniors nor seniors.
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Quantity A |
Quantity B |
The number of juniors in the class |
6 |
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
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Re: GRE Math Challenge #30-In the history class that consisted
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20 Feb 2018, 14:35
20 Feb 2018, 14:35
1
sandy wrote:
In the history class that consisted of 30 students, the number of seniors was 3 more than twice the number of juniors, and 3/10 of the students were neither juniors nor seniors
Column A: The number of juniors in the class
Column B: 6
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Column A: The number of juniors in the class
Column B: 6
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Let J = number of juniors in the class
Let S = number of seniors in the class
3/10 of the 30 students were neither juniors nor seniors
So, 7/10 were either juniors or seniors
7/10 of 30 = 21.
We can write: J + S = 21
...the number of seniors was 3 more than twice the number of juniors
We can write: S = 2J + 3
We now have the following system of equations:
J + S = 21
S = 2J + 3
Take the top equation and replace S with 2J + 3 to get; J + (2J + 3) = 21
Simplify: 3J + 3 = 21
Solve: J = 6
So, we get:
Quantity A: 6
Quantity B: 6
Answer: C
Cheers,
Brent
