(A) 1/2
(B) 1/4
(C) 3/5
(D) 4/7
Correct Option is: A
Given that, 40% play cricket; that is, P(C) = 40/100=4/10
20% play chess; that is, P(c) = 20/100 =2/10
And, 10% play both cricket and chess; that is, P(C And c) = 10/100 = 1/10
Now, we have to find the probability that 1 student plays cricket or chess; that we have to find, P(C or c)
We know that, P(C Or c) = P(C) + P(c) – P(C And c)
= 4/20+2/10-1/10 =5/10=1/2
Hence, the required probability 1/2