Question

in a group 100 people ,60 people like to play cricket ,20like to play both cricket and tennis.
How many people like to play tennis but not cricket?
solve by set theory

Answer 1

n(AUB)=100. (total number of people)
n(A)=60. (cricket)
n(B)=? (tennis)
n(AnB)=20. (both)
n(AUB)=nA+nB-n(AnB)
100=60+nB-20
100-60+20=nB
60=nB
n(B)=60