X and Y are two numbers where X >Y>1331.
The difference between the cubes of X and Y is D . Then ( D - 1 ) can be divisible by :

A ) X
B ) Y
C ) by 11
D ) by 3

• X^3-Y^3=D....let X=1333 and Y=1332....then (X-Y)=1
  (X-Y)^3=X^3-Y^3-3XY (X-Y)
  (X-Y)^3+3XY(X-Y)=X^3-Y^3
  1+3XY=D
  3XY=(D-1).....so (D-1) is divisible by 3
  
• 9 years agoHelpfull: Yes(48) No(4)
• Dear Supriti , last equationn yours was 3XY = ( D-1 ) means ( D - 1 ) is divisible by 3 , X as well as Y.
• 9 years agoHelpfull: Yes(15) No(1)
• the 4)option is all the above .. option given above is wrong ..
  
  option are
  A ) X
  B ) Y
  C ) divisible by 3
  D ) all the above
  
  the right answer is d. i have solved it and it was correct
• 9 years agoHelpfull: Yes(13) No(5)
• X^3-Y^3=D
  let X=1333 and Y=1332
  then (X-Y)=1
  (X-Y)^3=X^3 - Y^3-3XY (X-Y)
  (X-Y)^3+3XY(X-Y)=X^3-Y^3
  1+3XY=D
  3XY=(D-1)
  Since X and Y are complete numbers
  So (D-1) is divisible by 3
• 9 years agoHelpfull: Yes(5) No(0)
• wrong if you try with difference of more than one it will not be divisible by 3.......
  
  i mean try with 1332 and 1334
• 9 years agoHelpfull: Yes(2) No(0)
• let X be 13 & Y be 12.
  2197-1728=D
  D=469
  Now, 469-1=468
  then we have to check that 3 is divisible by 468.
  Hence, ans is D.
• 9 years agoHelpfull: Yes(1) No(13)
• d is the answer
  
• 9 years agoHelpfull: Yes(0) No(2)
• d is the answer
  
• 9 years agoHelpfull: Yes(0) No(1)
• Explain please
• 9 years agoHelpfull: Yes(0) No(0)
• Anyone got 13 Aug result..
• 9 years agoHelpfull: Yes(0) No(0)
• d is right answer
• 9 years agoHelpfull: Yes(0) No(1)
• @ ROHIT RAJ the question is can be not will be...
  so answer is d only
• 9 years agoHelpfull: Yes(0) No(0)
• @rohit raj.... u can't take 1332 and 1334...since in question asking that (D-1) not (D-2)
• 9 years agoHelpfull: Yes(0) No(1)
• ans is 3 let x is 14464 and y is 1728 diffrenece is 127366-1=127365 is divisible by 3
  
• 8 years agoHelpfull: Yes(0) No(0)
• Given, x>y>1331
  We know that, 1331= 11^3
  So we can assume y= 12^3 and X= 13^3
  D= 13^3 * 12^3
  D= 2197-1728
  D= 469
  Hence it will only be divisible by 3
  Therefore , option 'c' will be the answer
• 6 years agoHelpfull: Yes(0) No(0)