Mr. Wilson invested money in two accounts. His total investment was $30,000. If one account pays 7% in interest and the other pays 4% in interest, how much does he have in each account if he earned a total of $1,440 in interest in 1 year?
s = 7% , f = 4%
s + f = 30000
(s * .07) + [(30000 - s) * .04] = 1440
solve for s , then substitute back to find f