PLEASE HELP ME!A pharmacist has a 12% boric acid solution and a 20% boric acid solution. How much of each must he use to make 80 grams of a 15% boric acid solution?
Accepted Solution
A:
x = amount of
20% solution needed 80 grams - x = amount of 12% solution needed 20% = 0.2012% = 0.12
15% = 0.15
Write out the
equation:
0.20x + 0.12(80-x) = 0.15(80)
Distribute the
part in parenthesis:
0.20x + 9.6 - 0.12x = 12
Subtract 9.6
from each side and combine like terms:
0.20x - 0.12x =
12 - 9.6
0.08x = 2.4
Divide both
sides by 0.08:
x = 2.4/0.08
x = 30 grams of the 20% solution