Question:
If n+1Cr+1: nCr: n-1Cr-1 = 55: 35: 21 then the value of n + r is _____.
If n+1Cr+1: nCr: n-1Cr-1 = 55: 35: 21 then the value of n + r is _____.
Updated On: Jul 14, 2024
Hide Solution
Verified By Collegedunia
Correct Answer: 16
Solution and Explanation
The correct answer is 16.
Was this answer helpful?
1
1
Top Questions on permutations and combinations
- If the number of seven-digit numbers, such that the sum of their digits is even, is $ m \cdot n \cdot 10^a $; $ m, n \in \{1, 2, 3, ..., 9\} $, then $ m + n $ is equal to
- JEE Main - 2025
- Mathematics
- permutations and combinations
- The number of four digit even numbers that can be formed using the digits 0, 1, 2 and 3 without repetition is:
- KCET - 2025
- Mathematics
- permutations and combinations
- There are 12 points in a plane in which 5 are collinear such that no three of them are in a straight line. Then the number of triangles that can be formed from any 3 vertices from 12 points.
- JEE Main - 2025
- Mathematics
- permutations and combinations
- There are 12 points in a plane in which 5 are collinear such that no three of them are in a straight line. Then, the number of triangles that can be formed from any 3 vertices from 12 points.
- JEE Main - 2025
- Mathematics
- permutations and combinations
- The number of different 5 digit numbers greater than 50000 that can be formed using the digits 0, 1, 2, 3, 4, 5, 6, 7, such that the sum of their first and last digits should not be more than 8, is:
- JEE Main - 2025
- Mathematics
- permutations and combinations
View More Questions
Questions Asked in JEE Main exam
- The expression given below shows the variation of velocity \( v \) with time \( t \): \[ v = At^2 + \frac{Bt}{C + t}. \] The dimension of \( ABC \) is:
- JEE Main - 2025
- Thermodynamics terms
- The greatest value of \( n \), where \( n \in \mathbb{N} \), such that \( 3^n \) divides \( 50! \) is:
- JEE Main - 2025
- Number Systems
Match List-I with List-II.
Choose the correct answer from the options given below :- JEE Main - 2025
- Thermodynamics
- Let \( y = f(x) \) be the solution of the differential equation\[\frac{dy}{dx} + \frac{xy}{x^2 - 1} = \frac{x^6 + 4x}{\sqrt{1 - x^2}}, \quad -1 < x < 1\] such that \( f(0) = 0 \). If \[6 \int_{-1/2}^{1/2} f(x)dx = 2\pi - \alpha\] then \( \alpha^2 \) is equal to __________.
- JEE Main - 2025
- Differential equations
- Marks obtained by all the students of class 12 are presented in a frequency distribution with classes of equal width. Let the median of this grouped data be 14 with median class interval 12-18 and median class frequency 12. If the number of students whose marks are less than 12 is 18, then the total number of students is:
- JEE Main - 2025
- Statistics
View More Questions