Two investments total $1000. If the combined annual interest is $68, how much was invested at 8% and how much at 5%?

600 was invested at 8% and $400 at 5%

Step-by-step explanation:

Let x represent the amount of $ invested at 8% and y the amount at 5%.

Then x + y = $1000 is the total investment. Therefore, y = 10000 - x

Interest earned is then:

0.08x + 0.05 (y) = 68, or (after substitution)

0.08x + 0.05 (1000) - 0.05x = 68

0.08x + 50 - 0.05x = 68, or

0.03x = 18. Dividing both sides by 0.03, we find that x = 18/0.03 = 600.

If x = $600, then y = $1000 - $600 = $400.

$600 was invested at 8% and $400 at 5%.