Advertisements
Advertisements
प्रश्न
How many different selections of 5 books can be made from 12 different books if, Two particular books are always selected?
Advertisements
उत्तर
Total number of books = 12
Number of books to be selected = 5
Given Two books are always selected.
Remaining number of books to be selected = 3
The number of ways of selecting the remaining 3 books from the remaining 10 books = 10C3
= `(10!)/(3! xx (10 - 3)!)`
= `(10!)/(3! xx 7!)`
= `(10 xx 9 xx 8 xx 7!)/(3! xx 7!)`
= `(10 xx 9 xx 8)/(3!)`
= `(10 xx 9 xx 8)/(3 xx 2 xx 1)`
= 5 × 3 × 8
= 120 ways
APPEARS IN
संबंधित प्रश्न
Verify that 8C4 + 8C3 = 9C4.
How many chords can be drawn through 21 points on a circle?
How many triangles can be formed by joining the vertices of a hexagon?
There are 18 guests at a dinner party. They have to sit 9 guests on either side of a long table, three particular persons decide to sit on one side and two others on the other side. In how many ways can the guests to be seated?
In how many ways can a cricket team of 11 players be chosen out of a batch of 15 players?
- There is no restriction on the selection.
- A particular player is always chosen.
- A particular player is never chosen.
A committee of 5 is to be formed out of 6 gents and 4 ladies. In how many ways this can be done when
- atleast two ladies are included.
- atmost two ladies are included.
If nPr = 720(nCr), then r is equal to:
The value of (5C0 + 5C1) + (5C1 + 5C2) + (5C2 + 5C3) + (5C3 + 5C4) + (5C4 + 5C5) is:
If nPr = 720 and nCr = 120, find n, r
If `""^(("n" + 1))"C"_8 : ""^(("n" - 3))"P"_4` = 57 : 16, find the value of n
Prove that if 1 ≤ r ≤ n then `"n" xx ""^(("n" - 1))"C"_("r" - 1) = ""^(("n" - "r" + 1))"C"_("r" - 1)`
How many chords can be drawn through 20 points on a circle?
Find the number of ways of forming a committee of 5 members out of 7 Indians and 5 Americans, so that always Indians will be the majority in the committee
A box contains two white balls, three black balls and four red balls. In how many ways can three balls be drawn from the box, if at least one black ball is to be included in the draw?
How many triangles can be formed by joining 15 points on the plane, in which no line joining any three points?
Choose the correct alternative:
If 10 lines are drawn in a plane such that no two of them are parallel and no three are concurrent, then the total number of points of intersection are
Choose the correct alternative:
`""^(("n" - 1))"C"_"r" + ""^(("n" - 1))"C"_(("r" - 1))` is
Choose the correct alternative:
If nC4, nC5, nC6 are in AP the value of n can be
