Q1. Linear cost and revenue equations are shown below. Find the break-even quantity.

C(x) = 40x + 80, R(x) = 44x

Q2. A firm has fixed costs of $110,000 associated with the manufacture of lawn mowers that cost $220 per mower to produce. The firm sells all the mowers it produces at $420 each. Find the cost, revenue, and profit equations. Find the break-even quantity. (Let x be the number of mowers.)

C(x) = ? R(x) = ? P(x) = ?

break even quantity____?____ mowers

Q3. At Lincoln Library there are two ways to pay for copying. You can pay 7 cents a copy, or you can buy a plastic card for $8 and then pay 5 cents a copy. Let x be the number of copies you make. Write an equation for your costs for each way of paying. (Express C(x) in dollars.)

without card C(x) =

with card C(x) =

(a) How many copies do you need to make before buying the plastic card is the same as cash? ___?______ copies

(b) If you wish to make 398 copies, which way of paying has the least cost?

• without card
• they are the same
• cannot be determined
• with card