Question

The table shows how much a store charges for certain numbers of pencils. Number of pencils (p) Cost (c) 4 $0.72 7 $1.26 12 $2.16 Based on the table, which equation could be used to calculate the cost, c, of any number of pencils, p? A c = 0.09p B c = 0.18p C c = 0.54p D c = 0.72p ASAP SHOW YOUR WORK

Answer 1

Find the rate of change, (y2-y1)/(x2-x1), from the data given...

(2.16-1.26)/(12-7)=0.18

(1.26-0.72)/(7-4)=0.18

Since the rate is constant, this is a linear equation of the form y=mx+b.  Furthermore, since 0 pencils cost 0, b=0, so the cost of the pencils is simply the number of pencils times 18 cents...

c(p)=0.18p  (cost with respect to pencils is 0.18 times the number of pencils)