Consider the function M(n) defined on positive integers by M(n)=minimum of the digits of n;
For example, M(71) = min (7, 1) = 1.
The sum M(1) + M(2) + ... + M(90) equals
option
a) 284
b) 313
c) 302
d) 285
e) 286

• min digit from 1 to 10 is 1+2+3+..+9+0
  min digit from 11 to 20 is 1+1+1+1... 9times +0
  min digit from 21 to 30 is 1+(2+2...8times)+0
  from 31 to 40 its 1+2+(3+3... 7 times)+0
  and so on....
  solve
  the answr is 285
  
• 11 years agoHelpfull: Yes(50) No(5)
• 285 is the ans....
  
• 11 years agoHelpfull: Yes(9) No(1)
• 286 is ans...
• 11 years agoHelpfull: Yes(4) No(5)
• 285 will be the answe..
  
• 11 years agoHelpfull: Yes(4) No(2)
• 287 is the sum when u add all the numbers.
• 11 years agoHelpfull: Yes(2) No(2)
• e) 286 is soln
• 11 years agoHelpfull: Yes(1) No(0)
• @pawanpreet ...plz explain how?
• 11 years agoHelpfull: Yes(0) No(1)
• for 1-9...sum wil be 45.
  for m(10),m(20),....m(90)...sum=0
  for m(11-19)=9*1
  for m(21)=1 nd m(22-29)=8*2
  for m(31-32)=1+2 nd m(33-39)=(8-1)*tens place term
  "
  "
  "
  for m(81-87)=21+7=28 nd m(88-89)=2*8=16
  adding all...ans=285
• 11 years agoHelpfull: Yes(0) No(0)
• I guess this is a dummy question because to get 1 as min u have to consider 1,11,12,13,14..19 and also 21,31,41....upto 81
  thus u can get 17*1 for 1
  15*2 for 2
  13*3 for 3
  11*4 for 4
  9*5 for 5
  7*6 for 6
  5*7 for 7
  3*8 for 8 (for 88 and 89)
  1*9 for 9 (only when 9 will b considered)
  so total u can get 277 which is not in option
• 11 years agoHelpfull: Yes(0) No(0)