Q$1$a $-$ A drive$-$through process a McDonalds has three activities. The first activity is ordering; on average this process takes $2$ minutes. Then, a car proceeds to the payment window; on average this process takes $1$ minute. The last activity is picking$-$up the order, which on average this process takes $2$ minutes. There is a waiting before each of these activities. On average, there are usually $3$ cars waiting to place their orders; $2$ cars waiting to pay the total; and $1$ car waiting to pick$-$up order. On average $20$ cars an hour enters the line, and assume no cars leave this process until they pickup their order.