If P(n, r) = C(n, r) then - Vidyadip

MCQ

If P(n, r) = C(n, r) then

A
r = 0 or 2
B
r = 1 or n
C
r = 0 or 1
D
n = r

✓

Answer

(c) $r =0$ or 1
Explanation: Given $P ( n , r )= C ( n , r )$
$\begin{array}{l}\Rightarrow \frac{n!}{(n-r)!}=\frac{n!}{r!(n-r)!} \\ \Rightarrow 1=\frac{1}{r!} \\ \Rightarrow r!=1 \\ \Rightarrow r=0 \text { or } r=1[\because 0!=1,1!=1]\end{array}$

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 "M.C.Q (1 Marks)" from Model Paper 5→Model Paper 5 — all question types→MATHS STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

r and n are positive integers r > 1, n > 2 and coefficient of (r+2)th term and 3rth term in the expansion of (1 + x)²ⁿ are equal, then n equals:

Choose the correct answer.
The following information relates to a sample of size 60 $\sum\text{x}^2=18000$ and $\sum\text{x}=960,$ then the variance is:

A card is drawn at random from a pack of 52 cards. What is the probability that the card drawn is a spade or a king ?

$\cos 405^{\circ}=?$

Three integers are chosen at random from the first 20 integers. The probability that their product is even is:

$\frac{2}{19}$
$\frac{3}{29}$
$\frac{17}{19}$
$\frac{4}{19}$

If $A =\{2,4,5,7\}, B =\{2,3,4,6,8\}$ and a relation R is defined from set A to set B such that $x R y \Leftrightarrow x$ is divisor of $y$, then range of R is :

In a triangle ABC, a = 4, b = 3, $\angle\text{A}=60^{\circ}$ then c is a root of the equation:

$\text{c}^2-3\text{c}-7=0$
$\text{c}^2+3\text{c}+7=0$
$\text{c}^2-3\text{c}+7=0$
$\text{c}^2+3\text{c}-7=0$

What is the length of foot of perpendicular drawn from the point P(3, 4, 5) on y-axis.

$\sqrt{41}$
$\sqrt{34}$
$5$
$\text{None of these.}$

The number of ways in which 10 different diamonds can be arranged to form a necklace, is:

If $\text{f(x)}=\sin[\pi^2]\text{x}+\sin[-\pi^2]\text{x},$ where [x] denotes the greatest integer less than or equal to x, then: