a. Example--If one aspirin tablet contains five grains of aspirin, then how

many tablets will you give in order for the patient to receive 15 grains of aspirin?

The EXPRESSION OF STRENGTH is "one tablet contains five grains of

aspirin" and should be written as the first ratio of the proportion.

IF

THEN

1 tablet =

___________

5 grains

b. Next, assign "X" its proper place in the second proportion. Because the

question asks "How many tablets?" the "X" is placed opposite the tablets in the first

ratio.

IF

THEN

1 tablet = X tablets

5 grains

c.

The question asks you to calculate the number of tablets required in

order to give 15 grains of aspirin; therefore, the 15 grains will be placed opposite the

grains in the first ratio.

IF

THEN

1 tablet = X tablets

5 grains

15 grains

Prior to cross-multiplying, be sure that corresponding units in each ratio are

the same.

a. You have set up the proportion:

IF

THEN

1 tablet = X tablets

5 grains 15 grains

b. Now, cross multiply:

5(X) = 1(15)

MD0904

2-4

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