Combining different solution strengths
While organizing stock, the pharmacy manager finds 3 different bottles of isopropyl alcohol. She asks you to measure, consolidate, and re-label them into the largest container, which is a gallon bottle containing 1.5L of 90%. The second bottle contains 1L of 70%. The third bottle contained 1.25L of 70%. What will you write on the new label?
A. 74%-Isopropyl Alcohol
B. 81%-Isopropyl Alcohol
C. 86%-Isopropyl Alcohol
D. 78%-Isopropyl Alcohol
I don't even know where to begin with this. Please help. The answer is supposed to be 78%