There is no definitive answer to this question as it depends on a number of factors, such as the type of gum, the ingredients used, and how it is chewed. However, some brands of gum claim to last longer than others. For example, Orbit Gum advertises that its gum lasts up to five times longer than other gums.
To test which chewing gum lasts the longest, you would need to gather a variety of different types and brands of gum. You would then chew each piece for the same amount of time and compare how long they lasted. This could be done by measuring the time from when you start chewing until the flavor is gone or the gum becomes too hard to chew. You could also ask people to rate how long each piece lasted on a scale from 1-5, with 5 being the longest lasting.
Another way to test which chewing gum lasts longest would be to chew each piece for a set amount of time (e.g., one minute) and then see how much flavor was left after that time period. This could be done by rating the flavor on a scale from 1-5 or by measuring how much saliva was produced during chewing (the more saliva produced, the less flavor there is).
Finally, you could also look at how long each piece of gum takes to lose its shape when chewed vigorously. This could be done by seeing how long it takes for each piece to become flat or by measuring its thickness before and after chewing (the thinner it gets, the faster it loses its shape).