Question

A stock analyst deposited a total of $50,000 in two simple interest accounts. The annual simple interest rate on one account is 4%. The annual simple interest rate on the second account is 9%. How much was invested in each account if the total annual interest earned is 6% of the total investment?

Answer 1

Let 
x = amount invested at 9% interest, and
50000-x = amount invested at 4% interest

Then
0.09x+0.04(50000-x)=0.06*50000
Solve for x
0.05x=3000-2000
x=20000

The analyst invested $20000 at 9% and $30000 at 4%.