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 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 : After 55 years, a sum invested at simple interest at the rate of $r$ percent becomes twice of itself. What is the value of $r$?

Option 1: $\frac{17}{20}\%$

Option 2: $\frac{11}{30}\%$

Option 3: $\frac{13}{15}\%$

Option 4: $\frac{20}{11}\%$

Question : At a certain rate of simple interest per annum, a certain sum amounts to INR 24,000 in 7 years and to INR 32,000 in 12 years. What is the rate of simple interest paid per annum?

Option 1: 15%

Option 2: 25%

Option 3: 12.5%

Option 4: 20%

Question : The simple interest received on a sum at the rate of 8 percent per annum is $\frac{2}{5}$ of the sum. What is the period?

Option 1: 6 years

Option 2: 5 years

Option 3: 4 years

Option 4: 7.5 years