Dr. Miller's 600 kg car travels at 1.2 m/s until it hits Mr. Varn's 700 kg car and sticks to it. How fast do they travel together?
1.81 m/s
.55 m/s
1.2 m/s
1560 m/s

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 =