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 they be chosen?

Now a day's teenager's behavior is highly influenced under peer pressure without considering its pros and cons. Do you think that teachers' suggestion plays an important role in development of students' life?

Asked by Topperlearning User | 13th Sep, 2016, 03:04: AM

Expert Answer:

We have following cases:

(i) Three particular students join: now we have to choose 7 students from remaining 22 students

So number of ways = 22C7

(ii) Three particular students do not join. Here we have to choose 10 students from remaining 22 students

So number of ways = 22C10

Hence, total number of ways = C presuperscript 22 subscript 7 + 22C10 = 817190

Teachers' suggestion plays a very important role in development of students' life. They mould the students to bring out their skills or improvise them, teach good habits/attitudes and help them to become good citizens of the nation.

Answered by  | 13th Sep, 2016, 05:04: AM