statistics
posted by masaad .
Among the 500 first year students of college, 270 students study computer science, 345 students study mathematics, and 175 students study both computer science and mathematics. If one student is selected at random, find the probability that he did not take either of these subjects

1011

P[C.S]=270/500
P[Maths]=345/500
P[C.S ∩ Maths]=175/500
( P[C.S U Maths] )' = ?
ANS.
( P[C.S U Maths] )' = 1P[C.S U Maths]
=1{P[C.S] + P[Maths]  P[C.S ∩ Maths]}
=1{270/500 + 345/500 175/500 }
=1{440/500}
=10.88
=0.12 
A(5,3)<B (9,7)