The amount of water (in ml) that should be added to reduce 9 ml. Lotion, containing 50% alcohol, to a lotion containing 30% alcohol, is__________?
A. 3
B. 4
C. 5
D. 6
Explanation:
4.5 4.5
30% 70%
30% —– 4.5
70% ——? => 10.5 – 4.5 = 6 ml