Answer:
the ratio of the universe's helium to hydrogen by mass is 2:5 approximately.
Explanation:
To solve this question, we assign arbitrary values to these elements in tandem to the data given in the question.
nH, Number of Hydrogen atoms = X = 100
nHe, Number of Helium atoms = 0.1X = Y = 10
From the data given, by mass:
if the mass of Hydrogen atom = 1g = 100g
therefore, the mass of a Helium atom = 4g (1*4) = 40g
Mass ratio of Helium to Hydrogen = 40:100 = 4:10 = 2:5 approximately
