Question

There are 40 students in a class. Each students
sitting one after the other occupying bench
at a time. They got a task to count themselves
that how many students present on that
day. They started Counting from 1 and
finished at 38.
Q2 If students sitting at prime number of
Places went for Practisingcultural program
then how many students are left in the
Class.​

Answer 1

Answer:

equal marks. On one bit of paper, one arrangement of rank is to be written. 

Let the students be named as P,Q,R and S. 

Now, P can be treated as having rank I in 4 ways.

Q can be treated as having rank II in 3 ways.

R can be treated as having rank III in 2 ways.

S can be treated as having rank IV in 1 ways.

Therefore, total number of bits of paper required for all arrangement

=4×3×2×1=24