Lucia is a wonderful grandmother.Her age is b/w 50 to 70.Each of her sons have as many sons as they have brothers.Their combined number gives Lucia's present age?what is her age?

a)85 b)55 c)84 d)64

• If she has x sons
  each son has x-1 brothers.
  Total no of grandchildren=x(x-1)
  Total No OF Sons+Grandchildren= x+x(x-1)=x^2
  =>Lucia's age is a perfect square between 50 and 70. The only number that satisfies this condition is 64.
• 9 years agoHelpfull: Yes(26) No(0)
• since her age is btwen 50-70 so ans shuld b 55 or 64
  number of brothers is equal to number of sons so the number should b perfect square
  ans : d
• 9 years agoHelpfull: Yes(9) No(0)
• let there be S no.of sons,ie each have S-1 brothers
  now each son will have S-1 sons again ie total no of sons sons are=(S-1)*S
  so adding sons + sons sons=age
  S+S(S-1)=age
  S^2 = AGE so it must be perfect square
• 9 years agoHelpfull: Yes(1) No(0)
• 64
  BECAUSE X+(X-1)X=X^2
  THERE IS SQUARE NUMBER IS 64
  
• 9 years agoHelpfull: Yes(1) No(0)
• 64
  8*7=56 so only fall in that range
• 9 years agoHelpfull: Yes(0) No(3)
• X+5*(x-1)=grandmother age..... check by option
• 9 years agoHelpfull: Yes(0) No(4)
• 84=grandmother's age
• 9 years agoHelpfull: Yes(0) No(8)