The Answer To These Problems

Rod is paid an overtime rate of $25 per hour after he earns his basic wage of $600 per week. Write an equation in slope-intercept form for the total pay p if he works h hours of overtime.

The monthly cost C of Marge’s phone plan is given by C = 40 + m, where m is the number of extra minutes she uses in that month. Name the slope and y-intercept in this situation and explain what each represent.

Solution


1.) Rod is paid an overtime rate of $25 per hour after he earns his basic wage of $600 per week. Write an equation in slope-intercept form for the total pay p if he works h hours of overtime.

Slope-intercept form: y=ax+b

  1. the total pay p is our y; p=y
  2. h (number of hours overtime) is our x; h=x
  3. overtime rate of $25 per hour means that every hour (h) he gets $25 so we have 25 for the “a” or slope in the slope-intercept form; a=25
  4. basic wage of $600 per week means that that is a constant, and it’s fixed, it doesn’t change, so in the slope-intercept equation that is going to be “b”; b=600
  5. plug it in and get: p= 25h + 600

2.) The monthly cost C of Marge’s phone plan is given by C = 40 + m, where m is the number of extra minutes she uses in that month. Name the slope and y-intercept in this situation and explain what each represent.

C = 40 + m

If it’s not clear to you immediately, rewrite it like this:

C= 1m+ 40

And then compare it to slope-intercept form y=ax+b

That means that:

C=y

m=x

40=b which is y-intercept

a=1 which is the slope

So, slope is 1, and y-intercept is 40.