Lisa invests $4,000 in two types of bonds, bond A and bond B. Bond A offers a 10% return, and bond B offers a 6% return. Lisa invested in each bond in x and y amounts. To solve the problem using two equation: x +y =4000
0.10x + 0.06y = 340
Solving the equation lisa invested $2500 in 10% rate and $1500 in 6% rate.