Sally invested some money at 7% interest sally also invested 210$ more than 4 times that amount at 12% how much is invested at each rate if sally receives 2184.50 in interest after one year
Let's call the amount of money Sally invested at 7% interest "x".
Then the amount of money Sally invested at 12% interest would be "4x + 210$"
Since the interest is given as a percentage, we can multiply each investment by its respective interest rate to get the amount of interest earned:
7% of x = 0.07x
12% of (4x + 210$) = 0.12(4x + 210$) = 0.48x + 25.2$
The total interest earned is given as 2184.50$, so we can create an equation:
0.07x + 0.48x + 25.2$ = 2184.50$
Combining like terms and subtracting 25.2$ from both sides, we get:
0.55x = 2159.30$
To isolate x, divide both sides by 0.55:
x = 3926$
Then, we can substitute this value back into the equation 4x + 210$ to find the amount invested at 12%:
4(3926$) + 210$ = 15704$ + 210$ = 15914$
Therefore, Sally has invested 3926$ at 7% interest and 15914$ at 12% interest.