N atoms of gaseous helium are enclosed in a cubic vessel of volume t.0 cm 3 at

Question:

N atoms of gaseous helium are enclosed in a cubic vessel of volume t.0 cm 3 at room temperature. Find:
(a) The probability of atoms gathering in one half of the vessel;
(b) The approximate numerical value of N ensuring the occurrence of this event within the time interval t = 1010 years (the age of the Universe).