contestada

Kelly Fisher invested a total of $20,000 invested in two municipal bonds that have yields of 8% (bond A) and 10% (bond B) interest per year, respectively. If the interest Kelly receives from the bonds in a year is $1720, how much did she invest in each bond?

Respuesta :

Answer: Bond A = $14,000

Bond B = ₦6,000

Explanation:

We can solve by setting up mathematical equations.

Let A and B be used to express the dollar amounts invested at 8% and 10% respectively.

Capital invested equation becomes A + B = 20,000 - - - - - eq 1

Percentage interest equation becomes 8% of A + 10% of B = 1,720

To remove percentages we multiply through by 100, which gives

8A + 10B = 172,000 - - - - - - eq 2

So we have two simultaneous equations.

To solve, we multiply eq 1 by 10 so by subtraction we can eliminate B, then solve for A. Eq 1 becomes

10A + 10B = 200,000 - - - - eq 3

Subtract eq 2 from eq 3

(10A - 8A) + (10B - 10B) = 200000 - 172000

2A = 28000

A = 28000/2 = $14,000

A + B = 20000 from eq 1

Now A is 14000

14000 + B = 20000

B = 20000 - 14000

B = $6,000

Therefore capital invested is $14000 for bond A and $6000 for bond B