Math answers to homework

Question

Betsy a recent retiree, requires $6000 per year in extra income. She has $70000 to invest and can invest in b rated bonds paying 13% per year or in a certificate of deposit paying 5% per year. How much money should be invested in each to realize exactly $6000 in interest per year?

Answer 1

Let the amount in bonds = b. Then the amount in CD will be 70000 - b.

The interest from each will be added together to get 6000. In math, this becomes

0.13b + 0.05(70000 - b) = 6000

0.13b + 3500 - 0.05b = 6000

0.08b = 2500

b = 31250

So bonds = 31250 and CD = 38750