Question

The human body is 65% oxygen, 18% carbon! And 10% hydrogen. The rest is other elements. What percent is composed of other elements?

Answer 1

Well, simply young soul, you have to add up everything you have so far and subtract that by 100% because we know 100%= 100/100 just like 65%= 65/100, 18%= 18/100 and 10%= 10/100.
    65
    18               If all that added together is 93 we can put this over 100 just like
  +10               all the other ones.  93/100= 93%
---------            Now take the whole number (100) and subtract
   93               100-93= 7 which is 7%      
                      7% of the human body is made up of other elements. Hopes this 
                      helps!! :D

Answer 2

Is it 7%? im guesing u add them up