Advertisements
Advertisements
Question
Ten students are to be selected for a project from a class of 30 students. There are 4 students who want to be together either in the project or not in the project. Find the number of possible selections.
Advertisements
Solution
| Case I | Case II |
| 4 Students are in | 4 Students are out |
| Number of ways = 26C6 | Number of ways = 26C10 |
Required number = 26C6 + 26C10
APPEARS IN
RELATED QUESTIONS
Compute:
In how many ways can an examinee answer a set of ten true/false type questions?
In how many ways can six persons be seated in a row?
How many four digit different numbers, greater than 5000 can be formed with the digits 1, 2, 5, 9, 0 when repetition of digits is not allowed?
Serial numbers for an item produced in a factory are to be made using two letters followed by four digits (0 to 9). If the letters are to be taken from six letters of English alphabet without repetition and the digits are also not repeated in a serial number, how many serial numbers are possible?
If 28C2r : 24C2r − 4 = 225 : 11, find r.
From 4 officers and 8 jawans in how many ways can 6 be chosen. to include at least one officer?
Find the number of (ii) triangles
A committee of 7 has to be formed from 9 boys and 4 girls. In how many ways can this be done when the committee consists of: at least 3 girls?
If 20Cr = 20Cr−10, then 18Cr is equal to
In how many ways can a committee of 5 be made out of 6 men and 4 women containing at least one women?
The number of diagonals that can be drawn by joining the vertices of an octagon is
If n + 1C3 = 2 · nC2 , then n =
Find the number of ways of dividing 20 objects in three groups of sizes 8, 7, and 5.
Find the value of 80C2
A boy has 3 library tickets and 8 books of his interest in the library. Of these 8, he does not want to borrow Mathematics Part II, unless Mathematics Part I is also borrowed. In how many ways can he choose the three books to be borrowed?
In how many ways a committee consisting of 3 men and 2 women, can be chosen from 7 men and 5 women?
A bag contains six white marbles and five red marbles. Find the number of ways in which four marbles can be drawn from the bag if they can be of any colour
A bag contains six white marbles and five red marbles. Find the number of ways in which four marbles can be drawn from the bag if they must all be of the same colour.
Three balls are drawn from a bag containing 5 red, 4 white and 3 black balls. The number of ways in which this can be done if at least 2 are red is ______.
