Q.10. 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 ?
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, there are two cases :
The case I: All 3 off them join.
Then, the remaining 7 students can be chosen from 22 students in ways.
Case II : All 3 of them do not join.
Then,10 students can be chosen from 22 students in ways.
Thus, the required number of ways for the excursion of party