From a class of 25 students, 10 are to be chosen for an excursion party. There are 3 students who decide that either all of them will join or none of them will join. In how many ways can the excursion party be chosen?

In this question we get options that is

(i) Either all will go

Then remaining students in class are:

   

Number of students remained to be chosen for party

   

Number of ways choosing the remaining students

   

(ii) None of them will go

The students going will be

Remaining students eligible for going

   

Number of ways in which these students can be selected are

   

Total numbers of ways in which students can be chosen are