Question $2-$ A drive$-$through process a Subway has three activities. The first activity is ordering; on average this process takes $1$ minute. Then, a car proceeds to the payment window; on average this process takes $2$ minute. The last activity is picking$-$up the order, which on average this process takes $3$ minute. There is a waiting before each of these activities. On average, there are usually $1$ cars waiting to place their orders; $2$ cars waiting to pay the total; and $3$ cars waiting to pick$-$up order. On average $10$ cars an hour enters the line, and assume no cars leave this process until they pick$-$up their order.

a $-$ Clearly draw the process flow diagram for cars. Make sure you label each activity and buffer with appropriate Little's Law variables. $(6)$

b $-$ On average, how long does the entire process flow take? $(3)$