A amount doubles itself in 15 years. what is the rate of interest?

• let amount be x & rate of interest be r% annual then
  (2x-x)=(x*15*r)/100
  => 15r = 100
  => r=20/3 %
• 10 years agoHelpfull: Yes(35) No(6)
• let the principle be Rs. x
  as the amount double itself the interest is Rs. x too
  so x=x*r*15/100
  or r=100/15
• 10 years agoHelpfull: Yes(13) No(0)
• let amount(p)=x then s.i=x
  rate=(100*s.i)/p*t=(100*x)/(x*15)=100/15
• 10 years agoHelpfull: Yes(4) No(0)
• let principle=p and SI=p and T=15
  R=?
  formula;
  SI=P*R*T/100
  R=SI*100/P*T
  R=p*100/p*15
  R=100/15
  R=20/3
  ans: R=6.66%
• 10 years agoHelpfull: Yes(3) No(0)
• Ans:6.66
  here si,p is same.
  so by equation S=p*t*r/100;
  r=100/15
• 10 years agoHelpfull: Yes(2) No(0)
• let P=Principal
  A=amount
  SI=simple intrest
  R=Rate
  T=Time
  in first year SI=(P*R*1)/100
  therefore, amount A=P+SI=P+(P*R)/100
  NOW,after 15 years,
  SI=(P*R*15)/100
  Amount A'=P+(P*R*15)/100
  According to question, A'=2A
  therefore,2(P+(P*R)/100)=p+(P*R*15)/100
  =>2p+2(P*R)/100=P+15(P*R)/100
  =>P=13(P*R)/100
  =>R=100P/13P=100/13=33.33
  therefore ans is 33.33%
  
• 10 years agoHelpfull: Yes(1) No(9)
• let principal-p and SI-p and t-T
  R=(p*100)/p*15 after calculating 20/3
• 10 years agoHelpfull: Yes(1) No(0)
• [(n-1)/t] *100
  [(2-1)/15]*100
  (1/15)*100=20/3%
• 10 years agoHelpfull: Yes(1) No(0)
• as the time period is fixed so we will use simple interest formula ie.
  S.I= P*r*t/100
  S.I=A-P
  let P=x then it is given that amount doubles itself..
  so A=2x
  so S.I= (2x-x= x*r*15/100)
  on solving we get r=100/15
  ie.. r=20/3 %
• 10 years agoHelpfull: Yes(1) No(0)
• amt=si-p,here amt gets double so amt=2x of principal which is x.
  amt = 2x,p=x,
  si=p*r*t/100
  Ans.20/3 %
• 10 years agoHelpfull: Yes(0) No(0)