A woman made $45,000 during the first year of her new job at city hall. Each year she received a 10% raise. Find her total earnings during the first nine years on the job.

Answer 1

first year she made 45000
after two years she had 45000 + 45000(1.2)
after tree years she had 45000 + 45000(1.1)^2
...

This is a geometric series where
a = 45000
r = 1.1
n = 9

Now use your formula

Answer 2

45k
45(1+.1)
45(1+.1)^2
and so on. Isnt this a geometric series?

Sum a(1+.1)^n where n goes from 0 to 9

http://en.wikipedia.org/wiki/Geometric_series