Mathematics - Permutation & Combination Question with Solution | TestHub

MathematicsPermutation & CombinationnPr & nCrMedium2 minPYQ_2021

MathematicsMediumsingle choice

The sum of all the $4$ -digit distinct numbers that can be formed with the digits $1, 2, 2$ and $3$ is:

Answer:

Solution:

Digits are $1, 2, 2, 3$

total distinct numbers $\frac{4!}{2!} = 12 .$

total numbers when

$1$ at unit place is $3 .$
$2$ at unit place is $6$
$3$ at unit place is $3 .$

So, sum $= (3 + 12 + 9) (10^{3} + 10^{2} + 10 + 1)$

$= (1111) \times 24$

$= 26664$

Stream:JEESubject:MathematicsTopic:Permutation & CombinationSubtopic:nPr & nCr

⏱ 2mℹ️ Source: PYQ_2021

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