Principal x Rate = Interest

Question

Two investments totaling $43,000 produce an annual income of $1520. One investment yields 2% a year, while the other yields 6% per year. How much is invested at each rate

Answer 1

Here's what we know:

a + b = 43000

.02a + .06 b = 1520

 

Neither substitution nor elimination are that pretty, but we'll go with substituting in this for a in this case:

a = 43000 - b

.02(43000 - b) + .06 b = 1520

860 - .02b + .06b = 1520

860 + .04b = 1520

.04b = 660

Divide both sides by .04:

b = 16500

 

a = 43000 - 16500

a = 26500

 

So $26,500 is invested at 2%, and $16,500 at 6%.