An empirical formula is sort of like "We know the ratios of the elements but we don't know how much there is exactly of each element."
We first find the molar mass of CH4O and that is 1x12 +4x1 + 1x16=32g/mol.
32g/mol x n = 192 g/mol
n needs to be a whole number because you are multiplying each of the number of elements by n.
Molecular formula would be C6H24O6 since you multiply the number of each element by 6.