In a class of 10 students, roll numbers are written on their respective chairs. Find the ways in which exactly 4 students do not sit on their chairs.

In a class of 10 students roll numbers are written on their respective chairs. Find the ways in which exactly 3 students do not sit on their chairs .

In a class of 10 students roll numbers are written on their respective chairs. Find the ways in which exactly 3 students do not sit on their chairs .

Find the number of ways in which four persons can sit on six chairs.

In a class of 100 students exactly 15 students passed in Physics, exactly 20 stundents passed in Chemistry and exactly 45 students passes in Mathematics. If x_(1) and x_(2) are of maximum and minimum number of students respectively failed in all 3 subjects then :

In a class of 100 students exactly 15 students passed in Physics, exactly 20 stundents passed in Chemistry and exactly 45 students passes in Mathematics. If x_(1) and x_(2) are of maximum and minimum number of students respectively failed in all 3 subjects then :

The number of ways can 8 students sit round the table are

In a class of 25 students with roll numbers 1 to 25 , a students is pecked up at random to answer a question .Find students with roll numbers 1 to 25 , a student is picked up at random to answer a question . Find the probability that roll number of the selected students is either a multiple of 5 or 7.

Ten IIT students and 2 DCE students sit in a row.The number of ways in which exactly 3 IIT students sit in between 2 DCE students