A person invests $7,500 part at 5% and the remainder at 4% simple interest. If the total interest at the end of the first year was $346.50, find the amount invested at 4%.

Let x = amount invested at 5%
Let (7500 - x) = amount invested at 4%
0.05x + 0.04(7500 - x) = 346.50
HINT: Multiply each term by 100 to eliminate the decimals.
5x + 4(7500 - x) = 34650 Solve for x. I got x = 4650 and (7500 - x) = 2850

To find the amount invested at 4%, we substitute the value of x into the expression (7500 - x):

Amount invested at 4% = 7500 - x
= 7500 - 4650
= $2850

Therefore, the amount invested at 4% is $2850.