Rational expressions and equations

Question

WaRene's garden supply sells topsoil by the cubic yard. Five cubic yards of topsoil cost $102; nine cubic yards of topsoil cost $174. Assume a linear relationship fits these data with some ordered pair (yards,price). Find the linear equation for the data points and use the linear equation to find the cost of 13 cubic yards of topsoil.

Answer 1

Slope = (174 - 102)/(9 - 5) = 72/4 = 18

 

We can assume zero bags sell for $0, so...

 

y = 18x

 

y = 18(13) = 234

 

$234 for 13 yd³