1,2,3,4,5,6,7 are arranged in order of sum of consecutive numbers is prime number,how many ways we can arrange

• ans 5 ways.
  
  Explanation:
  1+2 = 3 (Prime no)
  2+3 =5 (Prime no)
  3+4 =7 (Prime no)
  5+6 =11 (Prime no)
  6+7 =13 Prime no)
  
  
• 8 years agoHelpfull: Yes(9) No(0)
• didn't get the question.. can anyone please explain..
• 8 years agoHelpfull: Yes(3) No(0)
• 
  ( Ans is: 22 ways )
  
  and the arrangements are:
  
  1 2 3 4 7 6 5
  1 2 5 6 7 4 3
  3 2 1 4 7 6 5
  3 2 5 6 7 4 1
  5 2 1 6 7 4 3
  5 2 3 4 7 6 1
  1 6 5 2 3 4 7
  1 6 7 4 3 2 5
  5 6 1 2 3 4 7
  5 6 7 4 1 2 3
  5 6 7 4 3 2 1
  7 6 1 4 3 2 5
  7 6 5 2 1 4 3
  7 6 5 2 3 4 1
  1 4 3 2 5 6 7
  1 4 7 6 5 2 3
  3 4 1 2 5 6 7
  3 4 7 6 1 2 5
  3 4 7 6 5 2 1
  7 4 1 6 5 2 3
  7 4 3 2 1 6 5
  7 4 3 2 5 6 1
  
  here we take any arrangement and add any two consecutive numbers of that arrangement we get prime number
  
  ex. 1 2 3 4 7 6 5
  the sum of two consecutive number from this is
  
  1 + 2 = 3
  2 + 3 = 5
  3 + 4 = 7
  4 + 7 = 11
  7 + 6 = 13
  6 + 5 = 11
  
  every time we get the prime number
  similarly in other arrangements also we get the prime number if we add two consecutive numbers of that arrangemet.
• 7 years agoHelpfull: Yes(1) No(3)
• Question is not clear. Tell us how many digits are there in a number. (2 digit number or 3 digit number or.........)
• 1 year agoHelpfull: Yes(0) No(0)