Question

ROn invested some money at 5% and $500 more at 7%. Hos total annual interest income was $215. How much did Ron invest at 5%?

Answer 1

did he spend 500 at 7% or 500 MORE than what he spent at 5%?
If he only spent 500 at 7%:
.05x + .07(500) = 215
.05x + 35 = 215
.05x = 180
x = 3600

If he spent 500 MORE than that of 5%:
.05x + .07(x + 500) = 215
.05x + .07x + 35 = 215
.12x = 180
x = 1500