Answer:
42
Step-by-step explanation:
To find the amount of water in a 63-kg person you must first find the unit rate in an 84-kg person.
84 ÷ 56 = 1.5
1.5 is how much human body weight there is as a unit rate over 1-kg of water.
1.5 x 56 = 84, so this shows we are correct.
84 ÷ 1.5 = 56, so that goes even further to prove you are correct.
Now, what's the amount of water in a 63-kg person?
1.5 is the unit rate we found out was used, so it should still be proportional.
63 ÷ 1.5 = 42.
Indeed, it is proportional. You are correct.
The answer is 42.
