Question 1206271
she needs 6000 per year.
she has:
50,000 total to invest.
b-rated bonds pay 17% per year
certificates of deposit pay 7% per year.
let x = value in b-rated bonds.
let y = value in certificates of deposit.
you have two equations that need to be solved simultaneously.
they are:
x + y = 50,000
.17x + .07y = 6,000
the overall interest rate will be 12% because .12 * 50,000 = 6000.
this was just a check to make sure that the highest interest rate investment would be enough to cover her interest requirements.
it does.
multiply both sides of the first equation by .17 and leave the second equation as is to get:
.17x + .17y = 8500
.17x + .07y = 6000
subtract the second equation from the first to get:
.10y = 2500
solve for y to get:
y = 25000


looks like she should invest 25000 in b-rated bonds and 25000 in certificates of deposit.
original equations becomes:
x + y = 25000 + 25000 = 50,000
.17x + .07y = 4250 + 1750 = 6000.


your solution is she should invest 25000 in b-rated bonds paying 17% and 25000 in certificates of deposit paying 7% to get a total annual interest of 6000 from both.