Thread: Word Problem

A clothing business finds there is a linear relationship between the number of shirts,n,it can sell and the price,p, it can charge per shirt. In particular, historical data shows that 9000 shirts can be sold at a price of $78, while 10000 shirts can be sold at a price of $70. Give a linear equation in the form p=mn+b that gives the price p they can charge for n shirts.

I cannot seem to solve for an equation as in p=mx+b

First, observe that you are given two points on the line, so we know its equation may be determined.

The two points are (9000,78) and (10000,70). From this, how may we determine the slope of the line?

You should be able to get the gradient of the line. Change in p is -$8, change in n is 1000. So m is -0.008. If you plug this in, you should be able to find b