Andrew earns an allowance of $14 the first week, $17 the next week, $20 the following week, and so on. How much will Andrew earn over the course of 10 weeks?
The final amount that he will earn is 14 + 9(3) = 14 + 27 = $41
So....the total amount that he earns =
[ First Week Amt + Last Week Amt ] * Number of Weeks / 2 =
[ 14 + 41 ] * 10 / 2 =
[ 55 ] * 5
$ 275
