Question

The amount of blood in a person's body, a quarts, is directly proportional to his or her body weight, w pounds. A person who weighs 128 pounds has about 4 quarts of blood. a) Find the constant of proportionality. b) Write an equation that relates the amount of blood in a person's body to his or her body weight. c) Find the weight of a person whose body has about 5 quarts of blood.

Answer 1

Explanation:

Let a represent the amount of blood in a Peron's body in quarts.

Let w represent the weight of the Peron's body in pounds.

Therefore,

a is directly proportional to w

a) Let k represent the constant of proportionality. Therefore,

a = kw

A person who weighs 128 pounds has about 4 quarts of blood. This means that

4 = k × 128

k = 4/128 = 0.03125

b) The equation that relates the amount of blood in a person's body to his or her body weight would be

a = 0.03125w

c) the weight of a person whose body has about 5 quarts of blood would be

5 = 0.03125w

w = 5/0.03125 = 160 pounds