Answer
a) $0.7$
b) $0.8$
Work Step by Step
a) Note that P(at least one) = P(one) + P(more than one)
Therefore, $P$(at least one)$ = 0.5 + 0.2 = 0.7$
b) Let A be the event that an order requests more than one feature. $P(A) = 0.2$ In the problem, we are looking for P(A').
$P(A') = 1 - P(A) = 1 - 0.2 = 0.8$
