Let's try to work this through.
1) Assume 100 g sample and multiply by percentages to find mass of each element
C=39.99g
H=6.79g
O=53.28g
2)Take mass of each element and convert to moles using molar mass from periodic table
Carbon→39.99g1⋅1mol12g=3.33 mol C
Hydrogen→6.79g1⋅1mol1.00g=6.79 mol H
Oxygen→53.28g1⋅1mol16g=3.33 mol O
3)Divide the moles by the smallest mole number of the three values
Carbon→3.333.33=1
Hydrogen→6.793.33=2.03≈2
Oxygen→3.333.33=1
4)Write out the element with their respected whole number mole ratios
C1H2O1
Answer:C1H2O1