Question

How many four digits numbers can be formed using 0,1,3,5,7,9 if repitation is not alowed

Answer 1

Answer:

36 four digit can be formed without any repitation . because if u observe this no. kinely then u can able to understand the pattern

Answer 2

✍︎......︎︎︎ᴥ︎︎︎︎︎︎ Aɴsᴡᴇʀ࿐

Total no. of digits are 5, i.e., n=5

Total no. of digits required is 4, i.e.,

r = 4

Therefore,

No. of 4 digits no. that can be formed =nPr=5P4=1!5!=120

No. of times each digit will appear =5120=24

Sum of digits at unit place =24(1+3+5+7+9)=24×25=600

Sum of all numbers =600×1000+600×100+600×10+600=666600

Hence the sum off all 4 diit numbers is 666600.

P.S: As 0 has no Value so I didn't mention it.

H O P E I T H E L P S !!!

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#PsʏᴄʜᴏHᴇʀᴇ

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