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varun.tinkle

FIND THE SUM OF THE NUMBERS FROM 1 TO 100 THAT I 1+2+3......+99+100 IN 2 MINUTES

THIS QUESTION WAAS ASKED BY LSE TO MY FATHERS BOSS WHO IS A MD AND HE COULDNT SOLVE IT

TO MY FATHERS FRIEND COULDNT SOLVE IT AND TO MY DAD COULDNT SOLVE .

UNFORTUNATELY I COULD SOLVE IT LETS SEE WHO CAN DO IT UNDER TIME LIMIT

varun.tinkle

AND MIND U
U CANT USE ANY FORMULA

rudra.panda

5050 n(n+1)/2 easy.

harsh15

see add the first and last digit:

100+1=101

simailarly now add 99+2=101

and go on.

this will occur 50 times.

hence 50*101=5050

hence the answer is 5050.No formula needed

Anant.Dutta

DaMN EASY PROBLEM
1+ 2+ 3..............................99+100=S
100+99+98...............................2+ 1 =S
THUS 2S=101+101+101........100 times
=101*100
thus S=101*500=50500

hamba

Gauss( my GURU) used the above process.

harsh15

ur ans is wrong man.

check it out.

rudra.panda

Sorry didn't see the next post.

S=100+99+98..........+3+2+1

S=1+2+3+.................+98+99+100

$2S=\underbrace{101+101+101\dots\dots 101}_{100\ times}$

2S=101*100

S=101*50

S=5050

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