A bank advertises that you can double the money if you invest it with them for 8 years, what is the rate of Interest offered by them?
a. 12.50% b. 10% c. 8.50% d. 14%

• simple formula
  I = (P*T*R)/100
  where p is principle amount
  t is time period
  r is rate of interest
  now they said that ur money will be doubled
  so interest becomes same as our principle amount
  so
  p=(p*t*r) /100,cancel p on both sides
  =>t*r=100
  =>r=100/t
  =>r=12.5 as given t=8
• 7 years agoHelpfull: Yes(19) No(0)
• Let x be the principle and r be the rate of interest,
  (x)=(x*r*8)/100
  Solve above equation we get n=12.5%
• 7 years agoHelpfull: Yes(5) No(2)
• SI=pnr/100 and amount=P+Pnr/100
  therefore, if p=100 then 200=100+100(8)(r)/100
• 7 years agoHelpfull: Yes(4) No(1)
• it will double the money implies you can invest how much you like! so for simplicity let you invested 100
  (100 +8years * 100* x/100) = 200 ( as 100 will be doubled)
  =} 8*100*X/100=100
  therfore x = 100*100/800*100 ==}} 12.5 SO OPTION A
• 7 years agoHelpfull: Yes(3) No(0)
• The rule states that an investment or a cost will double when:
  
  [Investment Rate per year as a percent] x [Number of Years] = 72.
  When interest is compounded annually, a single amount will double in each of the following situations:
  
  84X-table-10
  The Rule of 72 indicates than an investment earning 9% per year compounded annually will double in 8 years. The rule also means if you want your money to double in 4 years, you need to find an investment that earns 18% per year compounded annually.
  
  You can confirm the rationality of the Rule of 72 as follows: Find factors on the FV of 1 Table that are close to 2.000. (The factor of 2.000 tells you that the present value of 1.000 had doubled to the future value of 2.000.) When you find a factor close to 2.000, look at the interest rate at the top of the column and look at the number of periods (n) in the far left column of the row containing the factor. Multiply that interest rate times the number of periods and you will get the product 72.
  
  To use the Rule of 72 in order to determine the approximate length of time it will take for your money to double, simply divide 72 by the annual interest rate. For example, if the interest rate earned is 6%, it will take 12 years (72 divided by 6) for your money to double. If you want your money to double every 8 years, you will need to earn an interest rate of 9% (72 divided by 8).
• 7 years agoHelpfull: Yes(2) No(2)
• let you invest Rs 100.
  next after 8 years it doubles i.e Rs 200.
  8yrs - 100
  1yr - ?
  100/8=12.5
  therefore.... the rate of interest offered is 12.50%.
  or
  u can use formula total amount=p+(p.n.r)/100
  where, p is initial amount.
  n is number of years.
  r is rate of interest
• 7 years agoHelpfull: Yes(2) No(0)
• R=100*(1-z)/T......formula
  z=2
  t=8
  R=100*1/8=12.5%
• 6 years agoHelpfull: Yes(2) No(0)
• x=rt%(x)
  1=(8*r)/100
  r=12.5
• 7 years agoHelpfull: Yes(1) No(0)
• we will simply apply SI in this question: (x*8*r)/100=x
  now r=100/8=12.50% hence correct answer is (a)
• 7 years agoHelpfull: Yes(1) No(0)
• a.12.5%
• 7 years agoHelpfull: Yes(1) No(1)
• if total invest of money=100rs.
  then interest of 8 year= 8*12.50=100
  invest == interest
  100==(12.50*8=100)
• 6 years agoHelpfull: Yes(1) No(1)
• suppose invested 100
  after 8 years it becomes double means 200
  rate of interest is (200-100)/8=12.5%
• 6 years agoHelpfull: Yes(1) No(0)
• 12.5 is the rate of intrest
• 6 years agoHelpfull: Yes(0) No(1)
• if the money is doubled the interest amount after 8 years will be equal to pr
  SI=PNR/100.
  p=P*8*R/100.
  R=12.5
• 6 years agoHelpfull: Yes(0) No(0)
• c. p=2p
  r=25
• 6 years agoHelpfull: Yes(0) No(0)
• Let Principle=p, Amount in 8 years(time)= 2p. therefore, Interest I= A-P= 2p-p=p
  Now, We, know Rate r= I*100/(p*t). therefore r=> p*100/(p*t), which gives 100/8
  On solving we have r=12.50%
• 6 years agoHelpfull: Yes(0) No(1)
• let principal = Rs 100
  amount=2*100
  interest=200-100=100
  rate=i*100/p*t
  100*100/100*8=100/8=12.5%
• 6 years agoHelpfull: Yes(0) No(0)
• 12.50%...... 100/8
• 6 years agoHelpfull: Yes(0) No(0)
• let x=100
  100/8=12.50
  interest=12.50%
• 6 years agoHelpfull: Yes(0) No(0)
• given, A=2P ,T=8 year
  now we know, A=P+SI
  or, A=P+PRT/100
  or, 2P=P(1+RT/100)
  or, 2=1+RT/100
  or, 8R/100=1
  or, R=100/8=12.5%
• 6 years agoHelpfull: Yes(0) No(0)
• answer: c
  I is a vowel so it is not selected
• 6 years agoHelpfull: Yes(0) No(0)
• 100/8=12.5
• 5 years agoHelpfull: Yes(0) No(0)
• formulae r=100/t;
  r=100/8=12.5%
• 5 years agoHelpfull: Yes(0) No(0)
• 2x=x(1+(8y/100))
  100=8y
  y=r=12.50
• 4 years agoHelpfull: Yes(0) No(0)
• Let, Principal=100
  Time =8 years
  Simple interest= 2×P =200
  But the original amount = si - p =100
  
  100= 100×r×8/100
  r=12.5%
• 3 years agoHelpfull: Yes(0) No(0)
• 12.50%
  100/8
  because total amount add after 8 year is exactly amount of starting that amount that we invest
  so 1008
  and give it interest
• 2 years agoHelpfull: Yes(0) No(0)