Question

Maria began the school year with $200 in her school lunch account. The amount of money in the account has decreased linearly. After 4 months, she had $140 in her account. After 9 months, she had $65 in her account. Which function models the amount of money that Maria has in her account at the end of n months? O f(n) = 200 - 30n O f(n) = 200 - 15n O f(n) = 30n - 200 O f(n) = 15n - 200

Answer 1

Given :

The first amount of the money = $200

The amount of money in the account has decreased linearly.

After 4 months, she had $140 in her account.

So, the difference = 200 - 140 = 60

The rate of decrease will be = 60/4 = 15

As a check after 9 months , she had money = 200 - 9 * 15 = $65

So, the slope = -15

And the function will be :

`f(n)=200-15n`

So, the answer is option 2: f(n) = 200 - 15n