A mother wants to invest $15000 for her children's education. She invest a portion of the money in a bank certificate of deposit which earns 4 percent and the remainder in a savings bond which earns 7 percent. If the total interest earned after a year is $900 how much money was invested at each rate?

1 answer

b + s = 15000

.04 b + .07 s = 900

solve the system for b and s