Question 974165
The number of pupils minus 3
is a multiple of {{{12=4*3=2^2+3}}}, and is a multiple of {{{16=2^4}}}.
So, it is a multiple of {{{2^4*3=16*3=48}}} .
I would bet that the number of pupils minus 3 is
{{{1*48=48}}} and that the number of pupils is {{{48+3=51}}} .
 
NOTE:
Of course, it could be that the number of pupils minus 3 is
{{{2*48=96}}} and that the number of pupils is {{{96+3=9}}} ,
but this is a lot of pupils to have in one class,
It could be that the number of pupils minus 3 is
{{{3*48=154}}} , or {{{4*48=192}}} , or ....
but that would make the number of pupils be
{{{154+3=157}}} , or {{{192+3=195}}} , or ...
but those are even more ridiculously large numbers of pupils to have in one class.