Will spent 12.40 on three bags of chips how many would one bag of chips be?

12.40 / 3 = 4.133333333333333

Roughly $4.13 per bag of chips, however since 1/3 of a cent does not exist it's technically not possible to answer this question correctly. If he spent $4.13 per bag then that's only $12.39 total, and if it was $4.14 then it would be $12.42. Will must have rounded the final total.