Question

3.Use the graphic at the bottom. Developing a Roll of Film The Photo Lab $3.20 per roll plus 8¢ per print 24 EXP Specialty Photos $2.60 per roll plus 10¢ per print (a)Write equations that represent the cost of developing a roll of film at each lab. (b)Under what conditions is the cost to develop a roll of film the same for either store?

Answer 1

(a)

Photo Lab Cost = 3.20 + 0.08X

Specialty Photos Cost = 2.60 + 0.10X

(b) 30 prints is the number of prints needed for both costs to be the same

Explanation:

Let X be the number of prints processed. Noting that 8 cents is $0.08 and 10 cents is $0.10,

For Photo Lab, the equation for cost will be 3.20 + 0.08X

For Specialty Photos, the cost will be 2.60 + 0.10X

In order for both cost to be the same set both cost equations equal(break-even point)

2.60 + 0.10X = 3.20 + 0.08X

0.10X -0.08X = 3.20 -2.60

0.02X = 0.60

or

X = 0.60/0.02 = 30 prints

At prints developing photos at both shops will be the same and can be found by substituting for X in either equation

2.60 + 0.1(30) = 2.60 + = $5.60