Question : At a certain rate of interest per annum, compounded annually, a certain sum of money amounts to two times itself in 11 years. In how many years will the sum of money amount to four times itself at the previous rate of interest per annum, also compounded annually?

Option 1: 20 years

Option 2: 5.5 years

Option 3: 22 years

Option 4: 33 years

Question : A certain sum of money amounts to $\frac{3}{2}$ of itself in 2 years applying simple interest. Find the rate of simple interest per annum.

Option 1: 25%

Option 2: 15%

Option 3: 16%

Option 4: 26%

Question : A sum of Rs. 11,500 amounts to Rs. 12,880 in 2 years at the rate of simple interest. What is the rate of interest?

Option 1: 6% per annum

Option 2: 4% per annum

Option 3: 8% per annum

Option 4: 10% per annum

Question : A certain sum of money amounts to 3 times itself in 13 years when interest is compounded annually at a certain interest rate per annum. In how many years will the initial sum amount to 9 times itself at the same interest rate per annum, also compounded annually?

Option 1: 32 years

Option 2: 26 years

Option 3: 30 years

Option 4: 20 years

Question : A sum of money doubles itself in 12 years. Find the rate percent per annum of simple interest.

Option 1: 8.33%

Option 2: 6.25%

Option 3: 9.09%

Option 4: 11.11%