$10700 is invested in two different accounts. One account pays 18% simple interest per year and the other account pays 11% simple interest per year. If the total interest earn in one year is $1821.00, how much is invested at each rate?

Let $LaTeX: \displaystyle x$ be the amount invested at 18%. Then $LaTeX: \displaystyle 10700-x$ is amount invested at 11%. This gives the equation $LaTeX: \displaystyle 0.18 x+0.11(10700 - x)=1821$ . Solving for $LaTeX: \displaystyle x$ gives $LaTeX: \displaystyle x = 9200$ . So the amount in the other account is $1500.