the given exp (y)=1+(10+1)+(100+10+1)+......(102002+102001+.....1)
y=2002(1)+2001(1)+2000(10)..........+102002
How many 1s are there in the result of
1 + 11 + 111 + ... + 11..111 (which is 2002 ones) ????
vaise just to write the subject it is very easy.......though it applies some brain......
the given exp (y)=1+(10+1)+(100+10+1)+......(102002+102001+.....1)
y=2002(1)+2001(1)+2000(10)..........+102002
S = 1/9 ( 9 + 99 +999 +............._
S = 1/9( 10 + 100 + 1000 +.........2002 times.... - 1 -1-1-1-1-1-1-1.......2002 times..)
now its a cake walk....
Sum up the GP and total the -1sssss Ho gaya now count the ones manually [1]
arre EURE kya rite path.... pure ka pura sum to kar diya hai..... ab to sirf addition aur multi hi baki hai [1]