Question

Jimmy cell phone plan has been a base charge of $50 per month with an additional charge of 65 cents per app downloaded. Lisa cell phone plan has a base charge of $55 per month with an additional charge of 40 cents per app downloaded. How many apps will Jimmy and Lisa need to download for the bills to be the same?

Answer 1

20

Explanation:

We write what we know.

Jimmy

$50/mo app 65¢ or .65

Lisa

$55/mo app 40¢ or .40

a = number of apps

The difference will come from the number of apps, a.

We need them to equal each other so let's write an equation.

$50 + .65a = $55 + .40a

We need to solve for a.

$50 + .65a = $55 + .40a subtract $50 for each side.

$50 - $50 + .65a = $55 - $50 + .40a

.65a = $55 - $50 + .40a

.65a = $5 + .40a subtract .40a from each side

.65a - .40a = $5 + .40a - .40a

.65a - .40a = $5

.25a = $5 Divide each side by .25

.25a/.25 = $5/.25

a = $5/.25

a = 20

So Jimmy and Lisa need to download 20 apps for their bill to be the same.