Algebra problem

Question

A bank loaned out $18,000, part of it at the rate of 11% annual interest, and the rest at 5% annual interest. The total interest earned for both loans was $1,620.00. How much was loaned at each rate?

(Solve for x)

Answer 1

1620/18000 = .09 = 9%

9 is within 4 of 5 and within 2 of 11

you need 4/2 = 2 = twice as much invested at 11% as at 5%

$12,000 invested at 11% is twice $6,000 invested at 5%

.11(12,000) + .05(6000)= 1320 + 300 = 1620