at certain school

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at certain school

by ST » Mon Jun 22, 2009 9:05 am
At a certain school, 100 students are in the marching band. If 40% of the students in the orchestra are also in the marching band, how many students are members of neither the orchestra nor the marching band?

1. there are 1000 students in the school.
2. 50 students are in the orchestra.

Answer is C
Source: — Data Sufficiency |

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by nitya34 » Mon Jun 22, 2009 9:41 am
[only Orchestra] +[BOTH] + [ only marching band ] +Neither = Total

now lets take Orchestra=X
Neither=y

(1) gives us 0.60X+0.40X+(100-0.40X) + y=1000
=>0.60X+y=900

(2) X=50

[30] + [20] + [ 80] +y = Total


Combining we get y=870

hence C

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Thank you

by ST » Mon Jun 22, 2009 10:09 am
Thank you. You made the problem much easier.