how many three digit numbers can be form from digit 1-9 strictly in increasing order and follows an A.P.
A) 9
B)14
C)16
D) 12

• numbers are 123 135 147 159 234 246 258 345 357 369 456 468 567 579 678 789
  hence option c)16
• 7 years agoHelpfull: Yes(10) No(18)
• can anyone explain the ans of this question??
• 6 years agoHelpfull: Yes(2) No(0)
• here we need to take common difference of 1,2,3,4..
  e.g in 123
  common difference is 2-1=1 and 3-2=1
  again with common difference 2
  a new number is 135
  so there are 4 such numbers with starting digit 1
  now with starting digit 2 we can proceed the same way but we need to remember that the number must be in increasing order and Within 1 to 9...
  
• 7 years agoHelpfull: Yes(1) No(2)
• answer is 16
  123
  234
  345
  456
  567
  678
  789
  135
  357
  579
  246
  468
  147
  258
  369
  159
• 7 years agoHelpfull: Yes(1) No(1)
• 111,222,.....,999
• 7 years agoHelpfull: Yes(0) No(3)
• answer is 16
• 4 years agoHelpfull: Yes(0) No(0)
• 7 with common difference 1
  
  123,234,345,456,567,678,789
  
  5 with common difference 2
  
  135,246,357,468,579
  
  3 with common difference 3
  
  147,258,369
  
  1 with common difference 4
  
  159
  
  In total 16 numbers
• 2 years agoHelpfull: Yes(0) No(0)