is it true A balloon inflated with air has less mass than a marble.

Answer 1

Pick a number and you'll be right BECAUSE the answer could be anything.
How large is the marble?
What is the marble made of?
What is the density of the marble?
How large is the balloon?
How much air is in it?
What is the temperature of the air in the balloon?
What is the pressure of the air in the balloon?

Answer 2

no