Let x represent the amount of milligrams required for a person who weighs 140 lb.
We were told that the dosage of a cold medication is 2 mg for every 80 lb of body weight. The equations would be set up as shown below
2 = 80
x = 140
By crossmultiplying, we have
x * 80 = 2 * 140
80x = 280
We would divide both sides of th equation by 80. We have
80x/80 = 280/80
x = 3.5
Therefore, 3.5 milligrams of this medication are required for a person who weighs 140 lb