Answer: The total mass of the bag of 40 marbles is 120 grams.
Step-by-step explanation: Given that Pattie puts 40 marbles in a bag. Each marble has a mass of 3 grams.
We are to find the total mass of the bag of marbles.
We have
the mass of 1 marble = 3 grams.
Therefore, the mass of 40 marbles will be
[tex]=40\times 3\\\\=120~\textup{grams}.[/tex]
Thus, the required mass of the bag of 40 marbles is 120 grams.
