service $20$ minivans at any time, and has noted that servicing

a small bus is equirzlent in labour$-$hours and parts to servic$-$

ing two minivans. Similarly, servicing one large bus would be

equivalent to servicing four minivans. Based on school

enrollments, the school district has to be able to transport

$212$ students daily.

$($a$)$ Formulate a linear program to help the school

board decide how many of each type of bus to purchase.

$($b$)$ Solve using Excel.