Question

The weight of water in a person’s body varies directly as his/her body weight. The body of 170-lb person contains about 119-lb of water. How much water is in the body of a person who weighs 120-lb?

Answer 1

119-50 pounds = 69 so 169 pounds -step explanation: blood= weight (k)

Explanation:

y=kx

2

4.6 = 170k

finding the constant of variation

3

k= 0.02875

4

equation relates quarts of blood to weight

5

RESULT

4.6 = 170k

y= 0.02875x

y= 0.02875(175)= 5.03125

Answer 2

Ww=84 lb

Explanation:

Proportions

A direct proportion is a relation between variables where their ratio is a constant value. This means that if y and x are proportional, then:

y=k.x

Where k is the constant of proportionality.

The value of k is obtained by using the values of a specific point.

The weight of water Ww in a person's body varies directly as their body weight Wb as follows:

Ww=k.Wb

We are given a 170-lb person contains 119 lb of water. Substituting:

119=k.170

Solving for k:

k=119/170=0.7

The function is:

`Ww=0.7\cdot Wb`

To find how much water is in the body of a 120-lb person, we substitute Wb=120:

`Ww=0.7\cdot 120`

Ww=84 lb