Question

81 -

Answer 1

She pays in total $1350 after the 12 months

Step-by-step explanation:

The given is:

1. Daniela borrowed some money from her parents she agreed to pay

  $30 at the end of the  first month

2. She agreed to pay $15 more each additional month for months

We need to find how much money she pays in total after the 12 months

The formula of the sum of n terms of an arithmetic series is

$S_{n}=\frac{n}{2}[2a+(n-1)d]$, where a is the 1st term, d is the

common difference between each two consecutive terms, and n the

position of the term

∵ She will pay $30 at the end of the first month

∴ a = 30

∵ She will pay $15 more each month

∴ d = 15

∵ She will do that for 12 months

∴ n = 12

Substitute these values in the formula of the sum above

∴ $S_{12}=\frac{12}{2}[2(30)+(12-1)15]$

∴ $S_{12}=6[60+(11)15]$

∴ $S_{12}=6[60+165]$

∴ $S_{12}=6[225]$

∴ $S_{12}=1350$

She pays in total $1350 after the 12 months

Learn more:

You can learn more about arithmetic sequence in brainly.com/question/7221312

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