Question

The number of kilograms of water in a human body varies directly as the mass of the body. An 84-kg person contains 56 kg of water. How many kilograms of water are

in a 63-kg person?
kg of water are in a 63-kg person.
(Simplify your answer.)

Answer 1

Step-by-step explanation: Let the number of kilograms of water in human body be N and the mass of the body be M, from the statement ,

N ∝ M

introducing proportionality constant , we have

N = KM

Given from the second statement , N = 56 , M = 84

substitute the given values into the equation to get the constant

i.e 56 = K x 84

56/84 = k

therefore k = 2/3

substitute the value of K into the equation

i.e N = 2/3 M

Finally , to find N when M is 63

⇒ N = 2/3 x 63

therefore N = 42

There are 42 kg of water in a 63 kg person

Answer 2

42kg of water

Explanation:

84kg person contains 56kg of water

63kg person contains (x)kg of water

(x)kg of water = (63x56)/84=42kg of water