A sum of amount 12,000 doubles in 6 years at C,I.what will be the amount after 15 years?

• P = 12000
  n = 6
  Amount = P[1+ r/100]^n
  Given
  12000[1+ r/100]^6 = 2*12000
  [1 + r/100]^6 = 2
  Now P[1+ r/100]^15 = ?
  15/6 = 2.5
  So Amount after 15 years ll be 12000*(2)^2.5
  => 12000 * (2)^5/2
  => 12000 * sqrt(2) * sqrt(2) * sqrt(2) * sqrt(2) * sqrt(2)
  => 12000 * 4 * sqrt(2)
  => 48000 * sqrt(2)
  = 67872
  
  Ans : Rs. 67872
  
• 10 years agoHelpfull: Yes(3) No(0)
• initial amount= p=12000, final amount is double i.e a= 24000.formula= a=p[1+r/100]^n so 24000=12000[1+r/100]^6. 2=[1+r/100]^6-eqn(1) for 15 years, 12000[1+r/100]^15. multiplying power of eqn (1) by 5/2 on both sides, we get root 32 i.e 5.6. so [1+r/100]^15=5.6. ans = 5.6 * 12000=67,200
• 10 years agoHelpfull: Yes(1) No(0)