number of ways by which 4digit no made where aless than b,bless than c,c less than d where all lies between 1 to 9

• 126
  choose any 4 no from 1-9 only one way to arrange them, only one permutation possible per choice
  so the no of combinations of 4 out of 9 is the answer
  C (9 4) = 9!/(5!*4!) = 126.
• 11 years agoHelpfull: Yes(32) No(9)
• (I): Having first place as 1, total there will be 216(6^3) possible numbers.
  (II):Having first place as 2,total there ill be 125(5^3) possible combinations.
  (III): first digit 3,total 64(4^3) numbers.
  (IV):first digit 4,total 27(3^3) numbers.
  (V): If first digit=5,total 8(2^3) numbers.
  (VI): If first digit=6,possible number is only 1 (which is 6789).
  So,possible 4-digit numbers are=216+125+64+27+8+1=441.
• 11 years agoHelpfull: Yes(7) No(9)
• the correct answer is 126
  there are 9 digits to select from 1,2,3,4,5,6,7,8,9
  now we have to form 4 digit number .So the total number of selection of 4 digit number is C(9,4).
  Now within any selection there is only one possible way to arrange the digits otherwise condition is not satisfied if the digits are arranged.
  So the answer is given as C(9,4)*1 =126
  C(9,4) for selection and multiplication by 1 for 1 possible arrangement
• 11 years agoHelpfull: Yes(4) No(1)
• 360
  last digit fill by 6ways second last by 5 and so on
  3*4*5*6
• 11 years agoHelpfull: Yes(3) No(8)
• definitely its 9c4=126
• 11 years agoHelpfull: Yes(2) No(1)
• @prabin k ans 126 plz explain a bit
• 11 years agoHelpfull: Yes(0) No(1)
• c[9,4]=144
• 11 years agoHelpfull: Yes(0) No(2)
• answer is 63
  if abcd is no. and we know a
• 11 years agoHelpfull: Yes(0) No(3)
• I did it the hard may...but full and final answer is 126
• 11 years agoHelpfull: Yes(0) No(0)
• 456t46 is answer
  
• 10 years agoHelpfull: Yes(0) No(0)