Home › CA Foundation › quantitativeaptitude › Mathematics of Finance › Doubling period under the Rule of 72 at 9% per a…
Doubling period under the Rule of 72 at 9% per annum approximately equals
A7 years
B8 years
C9 years
D10 years
Answer & Solution
Correct answer: B. 8 years
1. Rule of 72 gives doubling time as 72 divided by rate.
2. T = 72 / 9.
3. T = 8.
4. So a sum doubles in approximately 8 years at 9%.
_Source: ICAI BoS Foundation Paper 3, Ch 4 'Math of Finance', p.10_
Related questions
The interest rate per period in CI when annual rate is 12% compounded quarterly isIf a loan of Rs.50000 is to be repaid in 5 equal annual instalments at 10% per annum, eachSinking fund deposit at end of each year to accumulate Rs.10000 in 5 years at 8% per annumThe interest on Rs.2500 for 5 years at simple interest is Rs.500. The rate isThe amount payable after 2 years on Rs.4000 at 5% per annum compounded annually isRs.16000 grows at compound interest to Rs.20736 in 2 years. The rate per annum isEqual monthly instalments needed to repay Rs.10000 in 1 year at 12% per annum approximatelThe present value of a perpetuity of Rs.100 per year at 5% per annum is