If a sugar compound has 11 oxygen atoms, how many hydrogen atoms does it contain?

The answer is:  22 hydrogen atoms.

Carbohydrates, including sugar, have a ratio of:

CₙH₍₂ₙ₎Oₙ  ;   so the number of hydrogen atoms will always be double the number of oxygen atoms;  the number of oxygen atoms will be always equal; the number of carbon atoms; the number of hydrogen atoms will always be be double the number of hydrogen atoms.  

So, we are given:  "a sugar compound has 11 oxygen atoms"; we know the compound will have twice that amount of hydrogen atoms; or, 11 * 2 (hydrogen atoms); or, 22 hydrogen atoms.