The cost of printing the school newspaper is $500 for 800 copies and $620 for 1200 copies. If the printing cost is a linear function of the copies printed, how do you find the cost of printing 1500 copies?

Question

6420 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-04-27T11:18:35

Cost of printing #1500# copies is # $710 #

This is a linear function, i.e obeys straight line equation:

Let y denotes cost in #$# and x denotes number of copies.

Slope #m= (620 -500)/(1200-800)= 120/400=3/10#

Equation of straight line is #y=mx+c or 500 = 3/10*800+c or 500 =240+c or c= 500-240=260#
Equation of straight line is # y = 3/10 x+260#

Check: #620 = 3/10*1200 +260 or 620 =360+260 or 620 =620#

Cost of printing #1500# copies is # y =3/10*1500+260 = 450+260 = $710 # graph{3/10 x+260 [-1280, 1280, -640, 640]} [Ans]