Sue has a total of $4000 to invest in two accounts. one account earns 2% simple interest and the other earns 5% simple interest. How much should be invested in both accounts to earn exactly $155 at the end of the year?

Answer 1

If $x go at 2%, the rest (4000-x) is at 5%. So, add up the interest on each part:

.02x + .05(4000-x) = 155.00