Question

Joe's Plumbing and Mark's Plumbing have different ways of charging their customers. The function defined by J(t)=45t represents the total amount in dollars that Joe

Plumbing charges for thours of work.
Mark's Plumbing charges $40 per hour plus a $25 trip charge.
Which plumbing service company has a higher rate per hour? Justify your answer.
A.Joe's Plumbing charges more per hour ($15) than Mark's Plumbing (S40).
B.Mark's Plumbing charges more per hour (540) than Mark's Plumbing (545).
C.Joe's Plumbing charges more per hour ($45) than Mark's Plumbing ($25).
D.Mark's Plumbing charges more per hour ($25) than Joe's Plumbing (545).

Answer 1

Joe's Plumbing charges more per hour ($45) than Mark's Plumbing (S40)

Explanation:

Let

t ------> the number of hours

J(t) ---->the total amount in dollars that Joe's Plumbing charges

M(t) ---->the total amount in dollars that Mark's Plumbing charges

we know that

The linear equation in slope form is equal to

`f(x)=mx+b`

where

m is the slope or rate of the linear equation

b is the y-intercept (initial value)

In this problem we have

Joe's Plumbing

`J(t)=45t`

The slope or rate is equal to

`m=\$45\ per\ hour`

`b=\$0`

Mark's Plumbing

`M(t)=40t+25`

The slope or rate is equal to

`m=\$40\ per\ hour`

`b=\$25`

therefore

Joe's Plumbing charges more per hour ($45) than Mark's Plumbing (S40)