help!

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ahsaf
Posts: 16
Joined: Mon Jan 19, 2015 10:48 pm
Location: dhaka, bangladesh

help!

Unread post by ahsaf » Wed Jan 21, 2015 9:38 pm

what is the sum of the digits from 1 to 2015 ?
Ex. sum of the digits from 19 to 21 is: 1+9+2+0+2+1=15.

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ahsaf
Posts: 16
Joined: Mon Jan 19, 2015 10:48 pm
Location: dhaka, bangladesh

Re: help!

Unread post by ahsaf » Sat Feb 07, 2015 10:23 pm

can't anyone find the answer :o i cannot do it so i posted it.
N:B:logic and reason must be given. :!:
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tanmoy
Posts: 281
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Location: Rangpur,Bangladesh

Re: help!

Unread post by tanmoy » Sat Feb 07, 2015 10:49 pm

I am giving you the process of solving it.I hope you will solve it own.
We want to count the sum of the digits of the number $1234567891011.........2015$.See that the sum of the digits from $1$ to $9$ is $45$.Now,the sum of the digits from $10$ to $19$ is $10\times1+45=55$.In this process you can count the total sum.
$\text{Another way}:$
Find the number of $1's$,number of $2's$...........number of $9's$ from $1$ to $2015$.
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Raiyan Jamil
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Re: help!

Unread post by Raiyan Jamil » Mon Feb 16, 2015 10:12 pm

This is the 7th question of junior category Dhaka 2015. The ans is 28098. :D
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