A survey of 100 person revealed that 72 of them had eaten at restaurant P and that 52 of them had eaten at restaurant Q. Which of the following could not be the number of the persons in the surveyed group who had eaten at both P and Q.
A 20 B 24 C 30 D 50 E 52
The answer is A
I don't know why ???Can someone give me a explaination ?
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- patrickgong6688
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- adrielfrederick
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Re: Question about Set
Hi Patrick,
Lets assume that 'x' is the number of people who ate at both P and Q and try to find out the maximum and minimum values of 'x'
The minimum value of 'x' can be calculated by
Only P + Only Q + P &Q = 100
72-x + 52-x + x= 100
which gives x to be 24 (Any number less than this wont add up to 100)
The maximum value of 'x' will be 52 since 52 people ate at restaurant Q and you cannot exceed that anyway
Therefore the range is between 24 and 52 and 20 is the only number out of range.
Do correct me if I am wrong
-Adriel
Lets assume that 'x' is the number of people who ate at both P and Q and try to find out the maximum and minimum values of 'x'
The minimum value of 'x' can be calculated by
Only P + Only Q + P &Q = 100
72-x + 52-x + x= 100
which gives x to be 24 (Any number less than this wont add up to 100)
The maximum value of 'x' will be 52 since 52 people ate at restaurant Q and you cannot exceed that anyway
Therefore the range is between 24 and 52 and 20 is the only number out of range.
Do correct me if I am wrong
-Adriel
- jnelson0612
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