If A and B are two events associated with a random experiment such that P(A) = 0.25, P(B) = 0.4 and P(A or B) = 0.5, find the values of

(i) P(A and B)


(ii)


(i)


Given : P(A) = 0.25, P(A or B) = 0.5 and P(B) = 0.4


To find : P(A and B)


Formula used : P(A or B) = P(A) + P(B) - P(A and B)


Substituting in the above formula we get,


0.5 = 0.25 + 0.4 – P(A and B)


0.5 = 0.65 - P(A and B)


P(A and B) = 0.65 – 0.5


P(A and B) = 0.15


P(A and B) = 0.15


(ii) Given : P(A) = 0.25, P(A and B) = 0.15 ( from part (i))


To find : P(A and )


Formula used : P(A and ) = P(A) – P(A and B)


Substituting in the above formula we get,


P(A and ) = 0.25 – 0.15


P(A and ) = 0.10


P(A and ) = 0.10


1