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Examples on P&C (Part III)
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Sachin Rana is teaching live on Unacademy Plus

Sachin Rana
IVth Year UG, IIT Bombay | YouTuber (143k subs) | Mentored 3 under 100 ranks in JEE Advanced | No. 1 educator for Organic Chemistry

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(11)
U
Unacademy user
sir in second question.... we can directly do 6*6! / 3!2!.....cann't we?
i didn't quiet understand the 1st question can you please help me?
We are basically calculating sum of individual digits of every number possible at every single position (ones, tens etc.) one by one and then multiplying it with its respective digits place and adding it up. This was only possible because, let's say at *ones* position every digit out (0,1,2,3) appears equal no. of times.
every digit out of*
Ishaan jain
8 months ago
Thnx
R
Rupesh
2 months ago
the sum is clear...but forming a four digit number from 0,1,2,3 would be in 3*3*2*1 ways...coz the number of digits are just four and repetition can't be allowed
R
Rupesh
2 months ago
the sum is clear...but forming a four digit number from 0,1,2,3 would be in 3*3*2*1 ways...coz the number of digits are just four and repetition can't be allowed
R
Rupesh
2 months ago
the sum is clear...but forming a four digit number from 0,1,2,3 would be in 3*3*2*1 ways...coz the number of digits are just four and repetition can't be allowed
10 lakhs wala question samajh nhi aaya sir !!
The total number of ways of doing this is 4!*5! = 2880. By placing the boys first by fixing one and arranging the rest of the girls.
Sachin Rana
a year ago
Correct. Good.
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