Two thermometers are calibrated one in degrees celsius and the other in degrees fahrenheit. at what temperature are their readings the same?

Both scales will read temperature at -40 degree C or - 40 degree F

Explanation:

As we know that two temperature scales are defined as

here we know that two temperature scales will read same values

so we will have

here we have

i'm on my way to history not a mistory.

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 =