a person starts write all 4 digits number how many times he has written the digit 2

1)when 2 is at unit place=9*10*10*1 [As,in thousand place 0 can't be placed.so it's 9 ]
2)when 2 is at tenth place=9*10*1*10
3)when 2 is at hundred place=9*1*10*10
4)when 2 is at thousand place=1*10*10*10
so total no. of 2s=900+900+900+1000=3700
11 years agoHelpfull: Yes(14) No(3)
total number of arrangements 9*10*10*10=9000
arrenments with no 2's 8*9*9*9=5832
so ans is 9000-5832=3168
11 years agoHelpfull: Yes(4) No(2)
at 1s place=900 times
at 10s place=900 times
at 100s place=900 times
at 1000 place = 1000 times
so total 3700
10 years agoHelpfull: Yes(2) No(0)
{4c1(9*9*9)-3}+{4c2(9*9)-3}+(4c3*9-1)+1=3432
only one 2+only 2 2s+ only 3 2s+ 1
11 years agoHelpfull: Yes(1) No(9)
the ans is 3519
11 years agoHelpfull: Yes(1) No(7)

a person starts write all 4 digits number how many times he has written the digit 2 ??