Question

Jack and Jill purchased cell phones. Jack's plan charges a fee of $24 plus $0.08 per minute he talks. Jill's plan charges a fee of $10 plus $0.15 per minute she talks. Which equation could be used to determine when Jack and Jill's plans will be the same?

Answer 1

Given:

Jack's plan charges a fee of $24 plus $0.08 per minute he talks.

Jill's plan charges a fee of $10 plus $0.15 per minute she talks.

To find:

The equation which is used to determine when Jack and Jill's plans will be the same.

Solution:

Let t be time in minutes.

Jack's plan charges a fee of $24 plus $0.08 per minute he talks. So, function for Jack's plan is

`f(t)=24+0.08t`

Jill's plan charges a fee of $10 plus $0.15 per minute she talks. So, function for Jill's plan is

`g(t)=10+0.15t`

Jack and Jill's plans will be the same, if
`f(t)=g(t)`.

`24+0.08t=10+0.15t`

Therefore, the required equation is
`24+0.08t=10+0.15t`.