There has to be a total of 63 boxes each with a prize in them.
There are two types of prizes: The first type is $25 and second type is $100.
If you make all the prizes $100, you will only end up with 27 prizes. ($2700 / 100), which is too little.
If you make all the prizes $25, you will only end up with 108 prizes ($2700/ 25), which is too way many.
The answer has to be combination of prizes More $25 prizes will have an outcome of more prizes in total.
More $100 prizes will have an outcome of less prizes in total.
The answer would come out to
48 prizes of $25 each ($1200)
15 prizes of $100 each ($1500)
which adds to the full amount of $2700 with 63 prizes.