Let's call A C10H8, B 12O2, C 10CO2, and D 4H2O.
The ratio is the division between two of the compounds.
For example, let's see the ratio between A and B:
[tex]\frac{A}{B}=\frac{1molC_{10}H_8}{12molO_2}=\frac{1}{12}=1\colon12,[/tex]Now, let's see the ratio between A and C:
[tex]\frac{A}{C}=\frac{1molC_{10}H_8}{10CO_2}=\frac{1}{10}=1\colon10,[/tex]The mole ratio between B and C:
[tex]\frac{B}{C}=\frac{12mol_{}O_2_{}}{10molCO_2}=\frac{6molO_2}{5molCO_2}=\frac{6}{5}=6\colon5,[/tex]And finally, the mole ratio between B and D:
[tex]\frac{B}{D}=\frac{12molO_2}{4molH_2O}=\frac{3molO_2}{1molH_2O}=\frac{3}{1}=3\colon1.[/tex]In this last example, you can interpret the mole ratios like this: three moles of O2 produce 1 mole of water (H2O). And so on with the other examples.