Question

I’M LOSING TIME!!!!!!

you are trying to decide which cell phone plan to purchase. Plan A chargeres $40 for a new phone and $20 a month for usage. Plan B provides the phone for free, but has a fee of $30 a month for usage.
Use the substitution method to determine when the two plans will cost the same.

Answer 1

Answer:

Step-by-step explanation:

Answer:

In 4 months the two plans will cost the same.

Step-by-step explanation:

Let $m$ represent the number of months of usage of phone

Let $C$ represent the total amount charged by the plans.

Plan A:

Plan A charges $40 for a new phone and $20 for per month usage.

Fixed charge = $40

Per month usage charge = $20

Usage charges in dollars for $m$ months will be = $20x$

Thus total charges $C$ in dollars can be given as:

A) $C=20m+40$

Plan B.

Plan B provides the phone for free, but has a fee of $30 for per month usage.

Fixed charge = $0

Per month usage charge = $30

Usage charges in dollars for $m$ months will be = $30x$

Thus total charges $C$ in dollars can be given as:

B) $C=30m$

In order to determine the number of month in which the two plans will charge same we will equate the equations.

Substituting equation B in equation A.

$30m=20m+40$

Solving for $m$

Subtracting both sides by $20m$

$30m-20m=20m-20m+40$

$10m=40$

Dividing both sides by 10.

$\frac{10m}{10}=\frac{40}{10}$

∴ $m=4$

Thus, in 4 months Plan A will cost the same as Plan B