Question 1189528
x + y = 80,000
.15 * x + .07 * y = 6000
x is the amount invested at 15%.
y is the amount invested at 7%.


these are to equations that need to be solved simultaneously.
multiply both sides of the first equation by .15 and leave the second equation as is to get:
.15x + .15y = 12000
.15x + .07y = 6000


subtract the second equation from the first to get:
.08y = 6000
solve for y to get:
y = 6000 / .08 = 75000.


this means x = 5000 because x + y = 80000
.15x + .07y becomes .15 * 5000 .07 * 15000 = 6000.


she should invest 5000 in the 15% bond and 75000 in the 7% bond.
that's your solution.