Question

Determine the milliliters of water needed to prepare 2 oz of a 10% solution from a 12.5% solution and distilled water.

Answer 1

Is that 2 fluid oz? or 2 oz in grams. I assume you mean 2 fluid oz which = 59.15 mL but check me out on that.

59.15mL x 10% = xmL x 12.5%.
solve for x. Then x mL of the 12.5% soln plus enough water to make 59.15 mL total.