How to figure out investments

Question

The Wright's have saved $15,600. They invest this money in three different accounts - a 1-yr CD that pays 3.2% annual interest, a high-interest savings account that pays 5.1% annual interest, and a money market account that pays 4.1% annual interest. They invest twice as much money in the high-interest savings account as the amount invested in the CD. Find the amount of money invested in each account if they earn $683.60 interest in 1 yr.

Answer 1

15600[(2*x*.051)+(x*.032)+(1-(3*x))*.041] = 683.60

---> x = .2564

High Interest: 15600 * 2 * x = 7999.68

1 yr CD: 15600 * x = 3999.84

Money Market: 15600 * (1-3x) = 3600.48