Question

Sam invests $6000 in treasury notes and bonds. The notes pay 8% annual interest and the bonds pay 10% annual interest. If the annual interest is $550, how much is invested in bonds?

Answer 1

$3500 in bonds.

Explanation:

8% = multiply by 0.08

10% = multiply by 0.10

Let `x` be amount in notes and `y` be amount in bonds.

`x + y = 6000`

`0.08x+0.10y = 550`

Multiply the second equation by 10:

`0.8x + y = 5500 implies y = 5500 - 0.8x`

Substitute in for `y` in the first equation:

`x+ (5500 - 0.8x) = 6000`

`0.2x = 500`

Multiply both sides by 5:

`x = 2500`

`implies y = 3500`