In how many ways can the letters of english alphabet be arranged so that there are seven letters in between A and B and no letter is repeated.
ans:
18*24!
24P7*2*18!
36*24!
24P7*2*20!

• A and B are fixed and can be arranged by 2!
  remaining letters=24
  Arrange 7 letters out of 24= 24P7
  Now consider A +7 letters+B as 1 letter, now remaining letters=26-9=17
  Then 1letter and 17 letters can be arranged by 18!
  i.e 24P7*2!*18!
• 9 years agoHelpfull: Yes(23) No(4)
• 24c7*7!*2!*18!=36*24!
• 9 years agoHelpfull: Yes(12) No(1)
• any no of alpha can come before "a" " _a_ _ _ _ _ _ _b _" any no of alpha can come after "b".
  to arrange
  a,b there are 2! ways
  7 digits between a & b = 24P7
  and
  remaining alphabet = let us assume a to b be 1 alphabet there fore the are total 18 alphabets hence we can arrange them in 18! ways
  
  since all are done simultaneously so ans= 24P7*2*18!
• 9 years agoHelpfull: Yes(7) No(2)
• actually value of option b and c are same.so we can go for any1
  
• 9 years agoHelpfull: Yes(1) No(3)
• 24P7*2*18!
• 9 years agoHelpfull: Yes(0) No(2)
• Ans is 24p7*2
• 9 years agoHelpfull: Yes(0) No(5)
• ans is .. 24C7 7!2!
• 9 years agoHelpfull: Yes(0) No(1)