How could the tiny drops of water get to the inside of the top cup

Small  drops of water are produced on the inside of the top cup because of the evaporated water  from the hot water in the bottom cup and then condensed  inside of the top cup. Condensation actually  happens one of two ways, it is either the air is chilled to its dew point or when it becomes very saturated with water vapor that it could not hold any more water. Furthermore, condensation could also create water droplets on the outside of  glasses of cold drinks or soda cans. When warm air reaches the cold surface, it gets to its dew point then it condenses. This is why there will be droplets of water on the can or glass.

your parents i think this could be it

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.