Q13/077) X=3^10000 Given log3=0.4771 All the digits sum of X =A All the digits sum of A =B All the digits sum of B =C find C

This is 4772 digits so A < 4772 * 9 or A < 50000

B < 41 so C <= 12 ( if b were 39)

X mod 9 = C mod 9

ax x mod 9 = 0 so C= 0 or 9 as it cannot be 18

as C cannot be zero it is 9