Question

Stella is a salesperson who sells computers at an electronics store. She makes a base pay amount each day and then is paid a commission as a percentage of the total dollar amount the company makes from her sales that day. Let P represent Stella's total pay on a day on which she sells x dollars worth of computers. A graph of P is shown below. Write an equation for P then state the y-intercept of the graph and determine its interpretation in the context of the problem.

Answer 1

step 1

Find the slope of the line

the slope is giving by the formula

m=(y2-y1)/(x2-x1)

we need two points

From the graph we take the points

(0,80) and (4000, 140)

substitute

m=(140-80)/(4000-0)

m=60/4000

m=6/400

m=3/200

m=0.015

step 2

Find the equation of the line in slope intercept form

P=mx+b

we have

m=0.015

b=80

therefore

P=0.015x+80

Remember that the y-intercept is the value of y when the value of x is zero

In this problem

the y-intercept represent a base pay amount each day

so

$80