Asample of propane, c3h8, contains 15.7 moles of carbon atoms. how many total moles of atoms does the sample contain?

Examining the sample, we find that each 3 moles of carbon combine with 8 moles of hydrogen.
The ration is thus 3:8

Based on this, we can calculate the number of hydrogen moles in the sample as follows:
number of hydrogen moles = 15.7 x 8 ∕ 3 = 41.8667 moles

Total number of moles in the sample = 15.7 + 41.8667 = 57.5667 moles

Iwould you figure it out but you don't have a picture or in your question as to what the physical property you're looking for is