Q. Number of 4digitd fomred unsing 1 2 3 4 5 5 6 6 .?

• 8 numbers can fill 4 slots in 8P4 ways
  therefore we have, 8*7*6*5
  however 2 numbers repeat, so, we divide this by 2!*2!
  the ans would be - 8*7*6*5/2!*2!=420 ways.
• 11 years agoHelpfull: Yes(41) No(1)
• 1.nos containing only 1,2,3,4,5 and 6:6C4x4!=360
  2.nos containing two 5's(Ex:5512):(5C2x4!)/2!=120
  3.nos containing two 6's(Ex:6612):(5C2x4!)/2!=120
  4.nos containing two 5's and 6's(Ex:5566):(4!)/2!x2!=6
  Total nos:360+240+6=606
  
  
• 11 years agoHelpfull: Yes(9) No(4)
• consider 1,2,3,4,5,6 (bcz given without repition)
  thousands place can be filled in 6 ways
  hunderdes place can be filled in 5 ways
  tens place can be filled in 4 ways
  units place can be filled in 3 ways
  so, ans will be
  6*5*4*3=360
  
  
• 11 years agoHelpfull: Yes(3) No(1)
• There are : one 1, 2 3 and 4
  two 5s and 6s.
  So nos. can be formed by choosing--
  i) 2C2*4!/(2!*2!) = 6
  ii) (2C1*5C2)*(4!/2!) = 240
  iii) 6C4*4! = 360
  
  Total = 6+240+360 = 606
• 10 years agoHelpfull: Yes(1) No(0)
• 8 no.can form with 8p4 =8*7*6*5 =1680
  here 5 & 6 occur twice times ,so they can arrange in 2!*2!
  so the answer would be the = 1680/ 2!*2!= 420
  
• 10 years agoHelpfull: Yes(1) No(0)
• last two digits by combining these are 12,16,24,32,36,42,52,56,64
  nine combinations are there
  now,
  according to fundamental of principle counting
  no. of digits are = (6*5*1)*9 = 270
• 11 years agoHelpfull: Yes(0) No(12)
• i think it is simple question of no repetition is allowed...
• 11 years agoHelpfull: Yes(0) No(3)
• 6*5*4*3=360
• 11 years agoHelpfull: Yes(0) No(2)
• 1.nos containing only 1,2,3,4,5 and 6:6C4x4!=360
  2.nos containing two 5's(Ex:5512):(5C2x4!)/2!=24
  3.nos containing two 6's(Ex:6612):(5C2x4!)/2!=24
  4.nos containing two 5's and 6's(Ex:5566):(4!)/2!x2!=6
  Total nos:360+48+6=414
• 11 years agoHelpfull: Yes(0) No(3)
• Containing 1,2,3,4,5,6 only: 6C2*4!=360
  Containing two 5's: 5C2*4!=120
  Containing two 6's: 5C2*4!=120
  Containing two 5's & two 6's: 4!/(2!*2!)=6
  Total No:360+120+120+120+6=520
• 11 years agoHelpfull: Yes(0) No(1)
• total no. of digit given=8.
  repeated digits=(5,5,6,6).
  no. of 4 digit formed=(8*7*6*5)/(2!*2!);
  since same digit. repeat at any position cause same value;
  ans:-420
• 10 years agoHelpfull: Yes(0) No(0)
• I think 8c4/2!2! as it is given that formed what we called as combinations instead of saying it is permutate(arranges) where we see a cricket is formed/committee members were formed...
• 10 years agoHelpfull: Yes(0) No(0)
• 8 numbers with 2 5s and 2 6s
  without repeat = 8*7*6*5/2! * 2!
  with repeat = 8*8*8*8/2! * 2!
• 10 years agoHelpfull: Yes(0) No(0)