Sherry saved $1800 she earned at her summer job. She invested part of her money in a Treasury Bill at 5% and the balance in a Money Market fund which guaranteed a return of 10%. If she earned $165 on her investments in the first year, how much was invested at each rate?

amount at 5% --- x

solve for x:

.05x + .1(1800-x) = 165

To solve this problem, we can set up a system of equations based on the given information.

Let's assume that Sherry invested x amount in the Treasury Bill at 5% and the remaining amount (1800 - x) in the Money Market fund at 10%.

The interest earned from the Treasury Bill would be (x * 0.05) and the interest earned from the Money Market fund would be ((1800 - x) * 0.10).

We are given that the total interest earned in the first year is $165. Therefore, we can write the equation:

(x * 0.05) + ((1800 - x) * 0.10) = 165

Now, we can solve this equation to find the value of x.

Simplifying the equation:

0.05x + 0.10(1800 - x) = 165
0.05x + 180 - 0.10x = 165
0.05x - 0.10x = 165 - 180
-0.05x = -15

Dividing both sides of the equation by -0.05:

x = (-15) / (-0.05)
x = 300

So, Sherry invested $300 in the Treasury Bill at 5% and the remaining amount ($1800 - $300 = $1500) in the Money Market fund at 10%.