Graphite is an example of carbon. what are the characteristics of graphite that make it suitable to be used as pencil lead?

Graphite is made of loosely bonded sheets of carbon atoms, due which it has a slippery texture. On the other hand that slippery texture makes it a very effective lubricant and thanks to this slippery quality, it also makes graphite a good material for pencil lead because it easily sloughs off onto paper.

28

Explanation:

(30+29+25+20+X)/5=25

30+29+25+20+X=125

104+X=125

X=21

The fifth number is 21.

The 3 largest numbers are 30, 29 and 25.

Their average is 28.