The solutions #1 and #2 are correct. Excellent!

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The answer is 11.

140 = 100 + 70 + 60 - 41 - 33 - 27 + x

x = 11

ganesh wrote:

SL # 1

In a school, it is found that 100 students play cricket, 70 play hockey, 60 play basketball, 41 play cricket and hockey, 33 play basketball and hockey and 27 play basketball and cricket. In total, 140 students play either one of more of these three games. Find the number of students who play all the three games.

39 nos

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Give explaination of your approach with your answer

]]>n(A U B U C) =

n(A) + n(B) + n(C) - n(AnB) - n(BnC) - n(AnC) + n(AnBnC)

Here, n(A U B U C) = 100-20 = 80

n(A) = 48, n(B) = 39, n(C)=44,

n(AnB)=17, n(BnC)=18, n(AnC)=22, n(AnBnC)=?.

Therefore, 80 = 48+39+44-17-18-22+n(AnBnC)

Therefore, n(AnBnC)=6.

Only A = 48-17-22+6 = 15

Only B = 39-17-18+6=10

Only C = 44-18-22+6=10.

Therefore, the number of professionals who read only one magazine is 15+10+10=35.

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In a survey of 100 computer professionals, it was found that 48

read *'Byte'*, 39 read* 'PC World'* and 44 read *'PC Magazine'*. It was also found that 17 read both Byte and PC World, 18 read both PC World and PC Magazine and 22 read both Byte and PC Magazine and the balance 20 read none of these 3 magazines. Determine the number of professionals who read exactly one magazine.