Question

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

Andrew earns an allowance of $12 the first week, $17 the next week, $22 the following week, and so on.

How much will Andrew earn over the course of 10 weeks?

Answer 1

$345

Explanation:

Answer 2

Answer: $345

Explanation:

The explicit rule for an arithmetic sequence is:
`a_n=a_1+d(n-1)\ \text{where}\ a_1\ \text{is the first term and d is the difference}`

In the given problem,
`a_1=12` and d = 5

`a_n=12+5(n-1)\\.\quad=12+5n-5\\.\quad=5n+7\\\\a_(10)=5(10)+7\\.\quad=50+7\\.\quad=57`

The sum of an arithmetic sequence is:
`S_n=(a_1+a_n)/(2)\cdot n`

`S_(10)=(12+57)/(2)\cdot 10\\\\.\quad=69\cdot 5\\\\.\quad=345`