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BDMO National Junior 2018/7
Posted: Tue Jan 08, 2019 1:53 pm
by nahin munkar
All possible $4$ digit numbers are created using $5,6,7,8$ and then sorted from smallest to largest. In the same manner, all possible $4$ digit numbers are created using $3,4,5,6$ and then sorted from smallest to largest. Then first number of the second type is subtract from first number of the first type, second number of the second type is subtract from second number of the first type and so on. What will be the summation of these difference (subtraction results) ?
BdMO National Junior problem 7
Posted: Thu Jan 10, 2019 1:49 am
by samiul_samin
You can get the problem here
Short solution
Re: BDMO National Junior 2018/7
Posted: Wed Jan 16, 2019 11:22 pm
by prottoy das
Probably it will be $4^4$ permutations. Because here, it is not said that a digit will be written one time in a number
Re: BDMO National Junior 2018/7
Posted: Thu Jan 17, 2019 1:48 pm
by samiul_samin
prottoy das wrote: ↑Wed Jan 16, 2019 11:22 pm
Probably it will be $4^4$ permutations. Because here, it is not said that a digit will be written one time in a number
I really missed that
