A diner is open from 6 a.m. to 6 p.m., and the average number of customers in the diner at any time can be

modelled by the function () = 30 cos (

6

) + 34, where h is the number of hours after the 6 a.m. opening

time. The average amount of money, in dollars, that each customer in the diner will spend can be modelled by the

function () = 3 sin (

6

) + 7