How should $27,500 be divided into two accounts, paying 7.5% and 5% interest, so that the total interest after one year is $1660?

Question

money problem 

Answer 1

Let x = the amount invested in the account paying 7.5% interest

Let y = the amount invested in the account paying 5% interest

x + y = 27,500       x = 27,500 - y

.075x + .05y = 1660      Multiply both sides of this equation by 1000 to remove the decimal points.

75x + 50y = 1,660,000

75(27,500-y) + 50y = 1,660,000

2,062,500 - 75y + 50y = 1,660,000

-25y = -402,500

y = $16,100

x = 27,500 - y = 27,500 - 16,100

x = $11,400