हिंदी

If Nc12 = Nc8 , Then N = (A) 20 (B) 12 (C) 6 (D) 30 - Mathematics

Advertisements
Advertisements

प्रश्न

If nC12 = nC8 , then n =

विकल्प

  • 20

  • 12

  • 6

  • 30

MCQ

उत्तर

20

\[n = 12 + 8 = 20\]  [∵ \[{}^n C_x =^n C_y \Rightarrow n = x + y or x = y\]]
shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 17: Combinations - Exercise 17.5 [पृष्ठ २५]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 11
अध्याय 17 Combinations
Exercise 17.5 | Q 7 | पृष्ठ २५

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

How many chords can be drawn through 21 points on a circle?


In how many ways can one select a cricket team of eleven from 17 players in which only 5 players can bowl if each cricket team of 11 must include exactly 4 bowlers?


A bag contains 5 black and 6 red balls. Determine the number of ways in which 2 black and 3 red balls can be selected.


In an examination, a question paper consists of 12 questions divided into two parts i.e., Part I and Part II, containing 5 and 7 questions, respectively. A student is required to attempt 8 questions in all, selecting at least 3 from each part. In how many ways can a student select the questions?


Determine the number of 5-card combinations out of a deck of 52 cards if each selection of 5 cards has exactly one king.


It is required to seat 5 men and 4 women in a row so that the women occupy the even places. How many such arrangements are possible?


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?


Compute: 

(i)\[\frac{30!}{28!}\]


Compute:

 L.C.M. (6!, 7!, 8!)


In how many ways can an examinee answer a set of ten true/false type questions?


Given 7 flags of different colours, how many different signals can be generated if a signal requires the use of two flags, one below the other?


How many different five-digit number licence plates can be made if

first digit cannot be zero and the repetition of digits is not allowed,


How many four-digit numbers can be formed with the digits 3, 5, 7, 8, 9 which are greater than 7000, if repetition of digits is not allowed?


How many 3-digit numbers are there, with distinct digits, with each digit odd?


Evaluate the following:

35C35


Evaluate the following:

n + 1Cn


If nC4 = nC6, find 12Cn.


If 8Cr − 7C3 = 7C2, find r.


If 28C2r : 24C2r − 4 = 225 : 11, find r.


How many different selections of 4 books can be made from 10 different books, if
there is no restriction;


How many different selections of 4 books can be made from 10 different books, if two particular books are never selected?


From 4 officers and 8 jawans in how many ways can 6 be chosen (i) to include exactly one officer


A student has to answer 10 questions, choosing at least 4 from each of part A and part B. If there are 6 questions in part A and 7 in part B, in how many ways can the student choose 10 questions?


Find the number of (ii) triangles


A business man hosts a dinner to 21 guests. He is having 2 round tables which can accommodate 15 and 6 persons each. In how many ways can he arrange the guests?


Write \[\sum^m_{r = 0} \ ^{n + r}{}{C}_r\] in the simplified form.


5C1 + 5C2 5C3 + 5C4 +5C5 is equal to


Total number of words formed by 2 vowels and 3 consonants taken from 4 vowels and 5 consonants is equal to


How many different committees of 5 can be formed from 6 men and 4 women on which exact 3 men and 2 women serve?
(a) 6
(b) 20
(c) 60
(d) 120


Four parallel lines intersect another set of five parallel lines. Find the number of distinct parallelograms that can be formed.


Find the value of 20C1619C16 


A student has to answer 10 questions, choosing atleast 4 from each of Parts A and B. If there are 6 questions in Part A and 7 in Part B, in how many ways can the student choose 10 questions?


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?


A convex polygon has 44 diagonals. Find the number of its sides.


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


To fill 12 vacancies there are 25 candidates of which 5 are from scheduled castes. If 3 of the vacancies are reserved for scheduled caste candidates while the rest are open to all, the number of ways in which the selection can be made is 5C3 × 20C9.


Number of selections of at least one letter from the letters of MATHEMATICS, is ______.


The number of numbers between 2,000 and 5,000 that can be formed with the digits 0, 1, 2, 3, 4, (repetition of digits is not allowed) and are multiple of 3 is?


There are ten boys B1, B2, ...., B10 and five girls G1, G2, ...., G5 in a class. Then the number of ways of forming a group consisting of three boys and three girls, if both B1 and B2 together should not be the members of a group is ______.


From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary are to be selected and arranged in a row on the shelf so that the dictionary is always in the middle. Then, the number of such arrangements is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×