Life is A Test 2: Test Harder (Quite A Bit Harder)

by Brony_of_Brody

The Answer 31

Record the mass of every single pack. The smallest difference in mass between any two readings must be equal to the smallest difference in amount of Prism Poppers - in other words, the mass of a single sweet.

However, this only works if the number of sweet packets is large enough for you to be sure that you'll have packs with consecutive whole number totals.