(3) The number 1 must be placed in the small square which has been added
to the center square of the matrix (see above).
Then
4000 X
1 = 4000 = 20
200
200
(4) The number 20 must be placed in the small square which has been
added to the higher strength square in the matrix (see matrix above).
(5) Once the fractions have been changed to whole numbers, solve the
matrix using the whole numbers. Assign the X and other known value to the proper
place on the matrix. The question should formulate the equation.
(6) Because the question asks, "How many milliliters of water?," and water is
0%, the X value will be placed on the 0% line. The 500-ml, because it pertains to the
1:200 solution, is placed on the 1:200 line (see paragraph 2-14c).
Then:
THEN
500
IF
1
19 =
X
cross multiply
X
=
9500 ml distilled water (answer)
d. Example 4: A pharmacist needs an elixir that contains 45% alcohol as a
vehicle for medication. On hand, he has a 10% alcoholic elixir and a 75% alcoholic
elixir. How many milliliters of the 75% elixir must be combined to make 1000 milliliters
of 45% alcoholic elixir?
Reduced:
(1) When solving for the amount of both ingredients when the final volume is
known, solve for the higher first. To solve for the higher, place the X on the line
opposite the 75% (see above). The only other known factor is that 1000 milliliters of the
45% must be prepared. The 1000-ml must be placed on the line opposite the 45%.
The arrow indicates that the bottom line is the 45% line (see above).
MD0802
2-37
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