You invested ​$12000 in two accounts paying 5 % and 9 % annual​ interest, respectively. If the total interest earned for the year was $ 1000 comma how much was invested at each​ rate?

Question

You invested ​$12000 in two accounts paying 5 % and 9 % annual​ interest, respectively.

If the total interest earned for the year was $ 1000 comma how much was invested at each​ rate?

Answer 1

If we let "x" be the amount invested at 5% (0.05), then "12,000 - x" will be the amount he invested at 9% (0.09) since there's a total of $12,000 to invest.The total interest earned would be the amount earned at 5% plus the amount earned at 9% or:

0.05x + 0.09(12,000 - x) = 1000

0.05x + 1080 - 0.09x = 1000

- 0.04x = - 80

x = 2,000

So was invested $2,000 at 5% interest and the rest ($10,000) at 9%.