How many molecules are in 3ch4?

The formula (3 \text{CH}_4) indicates that there are three molecules of methane (CH₄). Therefore, the total number of molecules is simply 3. If you need the number of individual atoms, each methane molecule contains one carbon atom and four hydrogen atoms, so there would be a total of 3 carbon atoms and 12 hydrogen atoms in 3 CH₄ molecules.