the square of two digit number(ab) divided by half of itself resultant added by 18 then divided by 2 then we get reverse of original number(ba). how many combination of ab exist
a) 9
b) 8
c) 7
d) 6

• (((10a+b)^2)/(10a+b/2)+18)/2=10b+a.
  Simplify the above equation.
  The final equation will be a-b=-1
  There will be 8 combinations of a &b which will satisfy this equation.
  i.e.
  a=1,b=2
  a=2,b=3
  a=3,b=4
  a=4,b=5
  a=5,b=6
  a=6,b=7
  a=7,b=8
  a=8,b=9
  
• 7 years agoHelpfull: Yes(25) No(0)
• 1- [{(ab)*(ab)}/{(ab)/2}+18]/2 = ba. this is the question .
  2- we can re write the expression as ab+9 =ba (try to solve the question, it is too easy ).
  3- you will get 8 no of combinations .(answer)
  those are
  12+9 =21
  23+9=32
  ...
  89+9=98
  * you cant take 01+9 = 10 , because o1 is a single digit no .
• 7 years agoHelpfull: Yes(5) No(3)
• b-a=1
  so total possible combination will be 8 by using the digit 1 to 9
• 7 years agoHelpfull: Yes(2) No(0)
• ans...8
  let number is n.=ab
  then n=10a+b..
  reverse num=ba=10b+a.
  now..((10a+b)^2/(10a+b)/2+18)/2=10b+a
  =>(2(10a+b)(10a+b)/(10a+b)+18)/2=10b+a
  =>(2(10a+b)+18)/2=10b+a
  =>(10a+b)+9=10b+a
  =>9a+9=9b
  =>a+1=b.
  and possible combination are..
  a=1,b=2
  a=2,b=3
  a=3,b=4
  a=4,b=5
  a=6,b=7
  a=7,b=8
  a=8,b=9
• 7 years agoHelpfull: Yes(1) No(0)
• plz sm1 explain how this eq reduced to a simple form
• 7 years agoHelpfull: Yes(0) No(0)
• @Sibabrat swain, your basics seem to be weak. For example take the second step:
  
  2- we can re write the expression as ab+9 =ba (try to solve the question, it is too easy ).
  Solution: ab+9=ba
  ab+9-ba=0
  ab-ba=-9
  0=9
  As ab and ba are the same numbers. You have to take 10a+b in the first step itself. ba is not the reverse of ab.
  Suppose, a=9 & b=8. => ab=72 and ba=> 72 also.
  
• 7 years agoHelpfull: Yes(0) No(2)
• but in the Q it is writen that ba is rev of ab so we cant do ab-ba=0
• 7 years agoHelpfull: Yes(0) No(0)
• Please tell the confirmed, verified and correct Answer, please comment on this fast
• 7 years agoHelpfull: Yes(0) No(0)
• ZAC
  what is the cyclic method?
• 7 years agoHelpfull: Yes(0) No(0)
• the square of 2 digit number divided by half of itself= is equal to double of that number
  and (double of that number+18)/2 = reverse that suggest they are combination of (x,x+1)
  so
  (12,23,34,45,56,67,78,89)= 8 combinations
• 6 years agoHelpfull: Yes(0) No(0)