Sets

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Sets

by venmic » Mon May 09, 2011 7:05 pm
The number of people who read book A is twice the number of people who read book B
The number of people who read book A and B is 500 which is twice the number of people who read only B
What is the number of people who read only A

1000

Please suggest how to approach

Thanx in advance!!

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by Anurag@Gurome » Mon May 09, 2011 7:52 pm
venmic wrote:The number of people who read book A is twice the number of people who read book B
The number of people who read book A and B is 500 which is twice the number of people who read only B
What is the number of people who read only A

1000

Please suggest how to approach

Thanx in advance!!
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by GMATGuruNY » Mon May 09, 2011 8:05 pm
venmic wrote:The number of people who read book A is twice the number of people who read book B
The number of people who read book A and B is 500 which is twice the number of people who read only B
What is the number of people who read only A

1000

Please suggest how to approach

Thanx in advance!!
The number who read both A and B is 500, which is twice the number who read only B.
Thus, only B = 250.
Total B = only B + both A and B = 250+500 = 750.

The number who read book A is twice the number who read book B.
Since total B = 750, total A = 2*750 = 1500.

Only A = total A - both A and B = 1500-500 = 1000.
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