in 1911, a french physicist Paul Langevin, devised a thought experiment based on Einstien's Special Relativity. In the experiment, a person makes a journey into space at narely the speed of light and comes back to the Earth. He Finds that he has aged five times less than his twin who stayed back on earth for 40years. This is popularly known as Twin Paradox. Now, consider the case of Hansel and Gretel, who are not twins. 9 years ago, Hansel was twice as old as Gretel. If they journey into space, an atomic clock assists in logging the start time of their journey accurately. If they do not journey into space, 9 years hence, Hansel's age will be 4 times the age of Greters. find Hansel's age today in binary numbers
a)11000 b)11011 c)1010 d)1001

• I think the last line of question is wrong,it should be 4/3 times instead of 413 or 4 times.
  then ,
  Let age of Hansel be h & age of Greters be g.
  h-9=2*(g-9)--1eq.
  h+9=(4/3)*(g+9)--2eq.
  eq2 - eq1:
  h+9-h+9=(4/3)*g-2g+(4/3)*9+18.
  =>18 = -(2/3)g+12+18.
  =>2g/3 = 12.
  =>g=(12*3)/2.
  =>g=18.
  now we put the value of g in 1eq.
  h-9=2*(g-9)
  =>h-9=2*(18-9)
  =>h-9=2*9
  =>h=18+9
  =>h=27
  Therefore, g = 18 Years
  h = 27 years.
  Now converting 27 in binary we get 11011.
  So, Ans will be option (b) 11011.
• 12 years agoHelpfull: Yes(13) No(1)
• i think the last line of question is wrong,it should be 4 times not 413 times.
  then ,
  let age of hansel be h & age of Greters be g.
  h-9=2g--1eq.
  h+9=4g--2eq.
  eq2 - eq1:
  h+9-h+9=4g-2g.
  =>g=9 yrs.
  so h=27 yrs.
  now converting 27 in binary ans will be option b)11011
• 13 years agoHelpfull: Yes(6) No(3)
• 100 coins in each bag,then 10 bags contain 1000
• 13 years agoHelpfull: Yes(1) No(21)