4. At a local pizzeria, delivery orders are handled by two employees, Enzo and Stella. Enzo takes care of \( 30 \% \) of the orders, while Stella handles the remaining orders. However, not all deliveries arrive on time. Stella is late with a probability of \( 15 \% \), while Enzo is late only \( 5 \% \) of the time. Suppose you ordered a pizza delivery.
(a) What is the probability that the delivery is on time?
(b) Your pizza delivery is running late. What is the probability that it is Enzo who will show up at you front door?