A student mixes 764 mL of water and 476 mL of 1.00 x 10-5 M orange food dye solution. What is the concentration of this new dilute solution of orange food dye?

Answer 1

Sorry, figured it out.
1.00E-5 x [476/(1240)]= 3.84E-6

Answer 2

That's right, assuming that the volumes are additive. Technically they are not but at these concentrations one never would be able to measure the difference.