Advertisements
Advertisements
प्रश्न
How many different selections of 5 books can be made from 12 different books if, Two particular books are always selected?
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.
The number of ways selecting 4 players out of 5 is
If nPr = 720(nCr), then r is equal to:
If nPr = 720 and nCr = 120, find n, r
Prove that `""^35"C"_5 + sum_("r" = 0)^4 ""^((39 - "r"))"C"_4` = 40C5
Prove that if 1 ≤ r ≤ n then `"n" xx ""^(("n" - 1))"C"_("r" - 1) = ""^(("n" - "r" + 1))"C"_("r" - 1)`
A Kabaddi coach has 14 players ready to play. How many different teams of 7 players could the coach put on the court?
How many chords can be drawn through 20 points on a circle?
How many ways can a team of 3 boys,2 girls and 1 transgender be selected from 5 boys, 4 girls and 2 transgenders?
How many ways a committee of six persons from 10 persons can be chosen along with a chair person and a secretary?
How many different selections of 5 books can be made from 12 different books if, Two particular books are never selected?
There are 5 teachers and 20 students. Out of them a committee of 2 teachers and 3 students is to be formed. Find the number of ways in which this can be done. Further find in how many of these committees a particular teacher is included?
In an examination a student has to answer 5 questions, out of 9 questions in which 2 are compulsory. In how many ways a student can answer the questions?
A committee of 7 peoples has to be formed from 8 men and 4 women. In how many ways can this be done when the committee consists of exactly 3 women?
A committee of 7 peoples has to be formed from 8 men and 4 women. In how many ways can this be done when the committee consists of at least 3 women?
How many triangles can be formed by joining 15 points on the plane, in which no line joining any three points?
