Question

A total of $3800 is invested into two accounts paying 4% and 7% annual interest. In one year the combined interest on the accounts is $218.
Find the amount invested at 4%.

Answer 1

To find the money you make, take: 

x(1 (+ or -) % interest rate) * Time


So in this case, it would be:

3800(1+0.04)(1) = Ans
and
3800(1+0.07)(1) = Ans

Assumably, combining those totals would give you $218. If you take the total of 3800(1+0.04)(1), subtract that from $218.

218 - (3800(1+0.04)(1)) = Your Answer