Acollege student earned $5100 during summer vacation working as a waiter in a restaurant on the boardwalk at the beach. the student invested part of the money at 8% and the rest at 9%. if the student received a total of $445 in interest at the end of the year, how much was invested at 9%?

$3700

Let x represent the amount invested at 9%. Then 5100-x is the amount invested at 8%. The total interest earned is ...

... 0.08(5100-x) +0.09x = 445

... 0.01x = 445 -0.08·5100 . . . . . collect terms, subtract .08·5100

... x = (445 -408)/0.01 = 3700 . . . divide by the coefficient of x.

The student invested $3700 at 9%.

answer:

24pi or letter c