Each of the small ice chests can hold a maximum of six cans of soda. There are 20 such chests. Therefore, the maximum number of soda cans that can be stored in these chests is 120.
10 of the ice chests are full, which means that there are 60 cans. We need to rearrange these cans such that each chest must have at least one soda can and every soda can should be there in a chest.
To maximize the number of chests that have exactly four cans, let’s start with the biggest number given in the options, which is option E.
If 15 chests have four cans each, it means that 5 cans do not have any cans at all. This violates the condition given in the question. So, option E is not the right answer.
Let’s look at option D. If 14 chests have four cans each, 56 cans out of 60 are in these 14 chests. The remaining 4 cans can be accommodated in 4 chests, but 2 chests will still be empty. Option D cannot be the right answer.
If 13 cans have four cans each, that’s 52 cans. We are left with 8 cans and 7 chests. Clearly, we can arrange so that every chest has at least one can. Therefore, option C has to be the right answer.
The most important point that needs to be realized here, is that the 60 cans are going to be rearranged among all the 20 cans, satisfying certain conditions. The moment you understand this part, is when you start getting closer to the right answer.
Hope this helps!