#Elitmus 30th Nov,2014 question.

How many 3 digits numbers are there whose
product of digits is 36? Options :
a)12
b)15
c)18
d)21

• x*y*z = 36
  where x,y,z are digits of number < 10
  
  (1,4,9),(1,6,6),(2,2,9),(2,3,6),(3,3,4) & its permutation.
  
  6 + 3 + 3 + 6 + 3 = 21 numbers
• 10 years agoHelpfull: Yes(47) No(1)
• No. of combinations possible are:
  (4,3,3) - 3!/2! ways=3 ways
  (2,6,3) - 3! ways=6 ways
  (2,2,9) - 3!/2! ways=3 ways
  (4,9,1) - 3!ways=6 ways
  (1,6,6) - 3!/2! ways=3 ways
  total= 3+6+3+6+3=21 ways
• 10 years agoHelpfull: Yes(14) No(0)
• option d 21
  factor of 36=2*2*3*3
  five basic no are 149,166,229,236,334 whoose product of digit is 36
  
  eg 149 rotate in 6 form 149,194,941,914,419,491
  236 rotate i also 6 form 236,326,362,263,623,632
  now 166 in 3 form 166,616,661
  229 in 3 form 229,292,922
  334 in 3 form 334,343,433
  so total combination is 6+6+3+3+3=21
• 10 years agoHelpfull: Yes(5) No(1)
• answer is 21
  
• 10 years agoHelpfull: Yes(1) No(0)
• i think 21 times..is it correct
• 10 years agoHelpfull: Yes(1) No(1)
• (2,2,9) -> total 3!/2=3
  (1,4,9) -> 3!=6 as no repetition
  (3,3,4) -> 3!/2=3
  (1,6,6) -> 3!/2=3
  (2,3,6) -> 3!=6
  so total 3 digit no= 3+6+3+3+6=21
• 9 years agoHelpfull: Yes(0) No(0)