Roberto invested some money at 7%, and then invested $2000 more than twice this amount at 10%. His total annual income from the interest was $3710. How much was invested at 10%?
A)$2800
B)$26,000
C)$6000
D)$28,000

Question

Quizplus · Accepted Answer

Let the amount invested at 7% be x dollars. Then, the amount invested at 10% is $2000 more than twice this amount, which is 2x + $2000. The total annual income from these investments is $3710. The interest from the first investment is 7% of x, or 0.07x, and the interest from the second investment is 10% of (2x + $2000), or 0.10(2x + $2000). The equation representing the total annual income is: 0.07x + 0.10(2x + $2000) = $3710. Solving this equation for x gives the amount invested at 7%, and then calculating 2x + $2000 gives the amount invested at 10%, which is $28,000.

Roberto Invested Some Money at 7%, and Then Invested $2000