Question

Susan purchased some municipal bonds yielding 7% annually and some certificates of deposit yielding 9% annually. if Susan's investment amounts to $19,000 and the annual income is $1,590, how much money is invested in bonds and deposits?

Answer 1

Certificates of deposits `=$.13000`
Bonds `=$.6000`

Explanation:

Susan buys bonds worth `=$.x`
She buys certificates of deposits worth `=$.y`

Yield from bond `=x xx 7/100=(7x)/100`
yield from certificates `=y xx 9/100=(9y)/100`

Then,

`x+y=19000` --------(1)
`(7x)/100+(9y)/100=1590` Multiplying both sides by 100, we get

`7x+9y=159000` -----(2)

Solving equation(1) for `x`, we get `x=19000-y`

Substitute `x=19000-y` in equation (2), we get

`7(19000-y)+9y=159000`

`133000-7y+9y=159000`

`133000+2y=159000`

`2y=159000-133000=26000`

`y=26000/2=13000`

`y=13000`

Certificates of deposits `=$.13000`

Substitute `y=13000` in equation (1)

`x+13000=19000`

`x=19000-13000=6000`

Bonds `=$.6000`