An investor has $500 more invested at 7% than he does at 5%..If his annual interest is $515, how much does he have inested at each rate?....I need to know how to solve this problem...Do I use PRT=I(interest) formula..please someone help me with the steps....

(Y+500).07 + y*.05=515

Yes, you can solve this problem using the formula PRT = I, where P represents the principal (or the amount invested), R represents the interest rate in decimal form, T represents the time (in years), and I represents the interest earned.

Let's call the amount invested at 5% x. According to the problem, the amount invested at 7% would be x + $500.

Now, we can set up two equations based on the given information:

Equation 1: x * 0.05 * T = I1
Equation 2: (x + $500) * 0.07 * T = I2

Since we are given that the total interest earned in one year is $515, we can set up a third equation:

Equation 3: I1 + I2 = $515

Now, let's substitute the values from the equations into Equation 3 and solve for x:

x * 0.05 * T + (x + $500) * 0.07 * T = $515

Simplifying, we have:

0.05xT + 0.07(x + $500)T = $515

Now, we can distribute and combine like terms:

0.05xT + 0.07xT + 0.07($500)T = $515

0.12xT + $35T = $515

Since the problem does not provide a specific value for T (time), we cannot solve for x directly. However, we can simplify the equation further:

0.12x + $35 = $515 / T

Now, we can isolate the variable x:

0.12x = $515 / T - $35

x = ($515 / T - $35) / 0.12

By substituting different values for T, you can determine the corresponding value of x, which represents the amount invested at 5%. Additionally, you can calculate the amount invested at 7% by adding $500 to the value of x.

Note: The specific value of T (time) is required to find the exact amount invested at each rate.