40+6.67=46.67, 100-46.67=53.33%O
C: 40/12=3.33 C: 3.33/3.33=1
H: 6.67/1=6.67 H: 6.67/3.33=2
O: 53.33/16=3.33 O: 3.33/3.33=1
Formula bruta: (CH2O)n
Se calculeaza masa moleculara si se egaleaza cu 60 (din problema):
(12*1+1*2+16*1)*n=60
30n=60, n=2, Se inlocuieste in formula bruta si formula moleculara va fi C2H4O2