Answer:
Each student is gonna sell 13 candy bars, and there is gonna be 1 bar unsold, because they sold equal amount of candy bars.
Explanation:
If there are 4 students, they need to sell 53 candy bars, and they will sell the same amount each one, we just have to divide:
, or

Because the division is not exact, we have a remainder of 1.
This can be interpreted as 1 candy is not sold, because they are gonna sell equally, so in that case each one would sell 13 candy bars, and one will be unsold.