The number of chocolate chips per cookie in Charlie's Chocolate Chip Cookie Shop is given by the following probability distributions, where X is the number of chocolate chips per cookie:

x 8 9 10 11 12
P(X=x) .1 .2 .4 .2 .1

a)Find the probability that a cookie chosen at random has at least 10 chocolate chips.
b) Find the probability that a cookie chosen at random has no more than 7 chocolate chips.

What I did:
a) P (x≥ 10 ) = .4+.2+.1=0.7
b) P (x ≤7) Is it zero?