how many three digit odd numbers can be formed from the digits 1,2,3,4,5 and 6 when
(a) repetition is not allowed
(b) repetition is allowed

• when repetition is not allowed
  last digit can be 1,3,5 ( 3 ways ) 1st digit can be 5 ways and 2nd digit can be 4 ways
  total 3*5*4=60 ways
  
  
  when repetition allowed
  last digit can be filled in 3ways and
  rest 2 digits can be filled in 6 ways each
  so total number of ways=3*6*6=108
• 11 years agoHelpfull: Yes(34) No(2)
• (a) when repetition is not allowed and number to be odd
  last digit will always have= 1,3,5 = 3 ways
  rest digit can be filled in = 5 ways first digit and 4 ways last digit
  tottal= 3 x 5 x 4 = 60 numbers
  
  (b)when repetition is allowed and number to be odd
  last digit will always have= 1,3,5 = 3 ways
  rest digit can be filled in = 5 ways first digit and 5 ways last digit
  total = 5 x 5 x 3 = 75 numbers
• 11 years agoHelpfull: Yes(0) No(27)