Correct Answer - B
We have
P(E)=P(X=2or,X=3or,X=3or,X=5or,X=7)
=P(X=2)+P(X=3)+P(X=5)+P(X=7)
=0.23+0.12+0.20+0.07=0.62
.
P(F)=P(X<4)
=P(X=1)+P(X=2)+P(X=3)
=0.15+0.12+0.12=0.50
.
P(E∩F)=P
(X is a prime number less than 4)
=P(X=2)+P(X=3)=0.23+0.12=0.35
∴P(E∪F)=P(E)+P(E)+P(F)-P(E∩F)
=0.62+0.50-0.35=0.77