Download App

Combinations — MATHS STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceMATHSCombinations3 Marks
Question
If ${^\text{n}}\text{C}_{12}={^\text{n}}\text{C}_{5},$ Find the value of n.
✓

Answer

We have, ${ }^n C_r=\frac{n!}{r!(n-r)!}$ Hence, $n=m r=12$ and 5 Applying formula ${ }^n C_p={ }^n C_q=n$ Then $p+q=n={ }^n C_{12}={ }^n C_5 12$ $+5=n \Rightarrow n=17$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "(Each question 3 marks)" from Combinations→Combinations — all question types→MATHS STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

Find the coordinates of the foci, the vertices, the length of major axis, the minor axis, the eccentricity and the length of the latus rectum of the ellipse.
$\frac{{{x^2}}}{4} + \frac{{{y^2}}}{{25}} = 1$
→
In a group of 950 person, 750 can speak Hindi and 460 can speak English. Find:
how many can speak both Hindi and English.
→
Find the sum of the following series to infinit:$\frac{1}{3}+\frac{1}{5^2}+\frac{1}{3^3}+\frac{1}{5^4}+\frac{1}{3^5}+\frac{1}{5^6}+\ ...\infty$
→
Let A = {1, 2} and B = {3, 4}. Find the total number of relation from A into B.
→
Find the general solutions of the following equations: $\tan^{2}\text{x}+(1-\sqrt{3})\tan\text{x}-\sqrt{3}=0$
→
Prove that: $\Big(2^{\frac14}.4^{\frac18}.8^{\frac{1}{16}}.16^{\frac{1}{32}}\dots\infty\Big)=2$
→
If the lines $2x - 3y = 5$ and $3x - 4y = 7$ are the diameters of a circle of area $154$ square units, then obtain the equation of the circle.
→
Find the sum to n terms of the sequences $8, 88, 888, 8888$, ……
→
Evaluate the following: $^{n+1}C_n$
→
Find the mean variance and standard deviation for the following data: $15, 22, 27, 11, 9, 21, 14, 9$.
→