What is the molecular formula if the percent composition is 58.8C 9.8H 31.4O

You only can calculate the empirical formula with that information. I can not guarantee the empirical formula is going to be the same than the molecular formula. To be able to calculate the molecular formula you need the molecular mass or other information.

58.8/12 = C = 4.9 = > 4.9/1.96 = 2.5 = > 2.5*2 = 5

9.8/1 = H = 9.8 = > 9.8/1.96 = 5 = > 5 * 2 = 10

31.4/16=O = 1.96 = >1.96/1.96 = 1 = > 1*2 = 2

empirical formula C5H10O2