8.Pe o anumita distanta, roata din fata a unui tractor face 15 rotatii in plus fata de cea din spate. Stiind ca circumferintele celor doua au lungimile de 2,5m si
respectiv 4m, determinati acea distanta d=?

answer: 31, 5556. 952 seconds

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =