Two matches, a bunsen burner, a balloon and a test tube?

Question

If you put two matches in a test tube and put a balloon over the top of the test and hold it over a bunsen burner the matches ignite letting off gas which goes into the balloon inflating it. How can modify it to
a) make the balloon inflate more and
b) Make the matches burn for longer period of time

Answer 1

More matches = More inflation
Bigger Test Tube = More Oxygen = Burn Longer

Answer 2

You can do neither. Since you cover the top of the test tube, there will not be enough oxygen for the matches to burn. If you want to make the baloon inflate more only option is you put more matches.