A sum of money triples itself at compound interest in 3 years. In 9 years it will be
a)6 times the principal b)12 times the principal
c)18 times the principal
d)27 times the principal

• let principal=100
  100 becomes 300 in 3 yrs
  300 becomes 900 in another 3 yrs
  900 becomes 2700 in another 3 yrs
  _______
  9 yrs
  hence amount is 27 times principal.
  
• 9 years agoHelpfull: Yes(38) No(0)
• 3p=p(1+r/100)
  now as per ques 3p^3=(p(1+r/100))^3
  thus (1+r/100)=27,,,, hence ans is 27 times the pricipal.
  Hope it will help you pratik
• 9 years agoHelpfull: Yes(6) No(2)
• p(1+ r/100) ^n=ci
  p(1+r/100) ^ 3=3p
  (1+r/100) ^3=3
  p(1+r/100) ^9=p(3)^3
  27 times
• 9 years agoHelpfull: Yes(3) No(3)
• rate is constant.
  in every 3 years, P(=sum of money) triples itlsef i.e. 3P.
  so, in first 3 years, P=3P
  in second 3 years, P=3P*3=9P
  in third 3rd years, P=9P*3=27P
  so, answer is d) 27 times the principal.
• 7 years agoHelpfull: Yes(2) No(0)
• Let the principal be x
  Amount in 3 years=3x
  3x=x(1+r/100)^3
  (1+r/100)^3=3
  In nine years amount=x(1+r/100)^9
  =x3^3
  =27x
  Answer option d
• 8 years agoHelpfull: Yes(1) No(0)
• d as c.i= p[1+r/100]^time
  so 3p = p[1+r/100]^3 => 3= [1+r/100]^3
  and c.i = p[1+r/100]^9
  using 2nd equtaion answer is 3*3*3= 27
• 8 years agoHelpfull: Yes(0) No(0)