Finding initial concentration

Hi all. I have a question on how to find initial concentration.

Here is the question:

Consider the situation in which 7.90 mL of an aqueous CuSO4 solution of unknown concentration is diluted to a volume of 15.00 mL. Through the measurement of absorbance, the final concentration of the solution is found to be 0.150M. What is the concentration of the initial solution of CuSO4?

We're on Beer's Law, so I thought to use A=ebc. However after re-reading the question, I did this:

MiVi = MfVf

Using the equation above, I found my Mi to be 0.285M

Is this the correct answer? If not, how do I go about finding the correct method for next time?

Thanks guys.

(0.150 M) x (15.00 mL) / (7.90 mL) = 0.285 M

You are correct.