Some Mathematics

I remember helping a friend carry her bag which was weighing around 5kg.

Y: Hey dont, let me do it myself.

me: nah its ok! Its nothing to me.

Y: Nevermind, i can carry myself.

Me: ok this thing is around 5kg. What is your weight?

Y:40kg

Me: So this thing is 0.125 of your weight. Not too small..

Me: But my weight is 80kg. So this thing is only 0.0625 of my weight. It is 2 times lesser than and thus can be considered negligible right?

She laughed and got nothing to say..

LOL