A restaurant sells about 330 sandwiches each day at a price of $6 each. For each $0.25 decrease in price, 15 more sandwiches are sold per day. How much should the restaurant charge to maximize daily revenue? What is the maximum daily revenue?

Answer 1

revenue = price * quantity, so if there are x price decreases, we have revenue is

y = (6-.25x)(330+15x)
= -3.75x^2 + 7.5x + 1980

Now, just find the vertex of that parabola to get the maximum revenue and its price. Recall that for

ax^2+bx+c

the vertex is at x = -b/2a