Answer: she invested $2500 at the rate of 10%.
she invested $1500 at the rate of 6%.
Step-by-step explanation:
Lisa invests $x in bond A and $y in bond B.
Lisa invests $4,000 in two types of bonds, bond A and bond B. This means that
x + y = 4000
Bond A offers a 10% return, and bond B offers a 6% return. Therefore,
Interest on bond A is 0.1x
Interest on bond B is 0.06y
Her total return on the investment is $340. It means that
0.1x + 0.06y = 340
Therefore, The system of linear equations defining the situation is
x + y = 4000
0.1x + 0.06y = 340 - - - - - - - - - - -1
Substituting x = 4000 - y into equation 1, it becomes
0.1(4000 - y) + 0.06y = 340
400 - 0.1y + 0.06y = 340
- 0.1y + 0.06y = 340 - 400
- 0.04y = - 60
y = - 60/ - 0.04
y = 1500
x = 4000 - 1500
x = 2500
