Word question involving interest and investment.

Question

A person has $10,000.00 to invest, he puts the money into two Banks. One gives 2% interest, the other 4%, the total interest he got in a year was $320.00, how much did he place into each bank?

Answer 1

Let x = the amount of money invested at 2% interest

Let 10,000 - x = the amount invested at 4% interest

.02x + .04(10,000-x) = 320     Multiply both sides by 100.

2x + 4(10,000-x) = 32,000

2x + 40,000 - 4x = 32,000     Subtract 40,000 from both sides.

                      -2x = -8000       Divide both sides by -2.

                         x = $4000, invested at 2%

10,000 - x = 10,000 - 4000 = $6000 invested at 4%