Ontario Registered Pharmacy Technician (RphT) Practice Exam

The final strength of the solution is 5%. This is because the total volume of solution has increased from 500mL to 1500mL, resulting in a dilution of the original 15% solution. This means that the concentration of the solution has decreased, and 5% is the remaining concentration after dilution. Option A is incorrect because it incorrectly assumes that the concentration would increase after dilution. Option C and D are incorrect because they show fractions rather than a percentage, which is the typical unit for solution concentration.