Question : A sum of money doubles itself in 7 years at simple interest. In how much time will it become 5 times itself?

Option 1: 25 years

Option 2: 28 years

Option 3: 23 years

Option 4: 21 years

Question : In how much time will the simple interest on a certain sum of money be $\frac{6}{5}$th times of the sum at 20% per annum?

Option 1: 7 years

Option 2: 8 years

Option 3: 5 years

Option 4: 6 years

Question : In how many years will a sum of Rs. 3000 yield an interest of Rs.1080 at 12% per annum simple interest?

Option 1: $4$ years

Option 2: $3$ years

Option 3: $5$ years

Option 4: $2\frac{1}{2}$ years

Question : At what rate of simple interest per annum will a sum of money triple itself in 16 years?

Option 1: 11.5%

Option 2: 11%

Option 3: 12%

Option 4: 12.5%

Question : If a sum of money becomes Rs. 4000 in 2 years and Rs. 5500 in 4 years and 6 months, at the same rate of simple interest per annum, the rate of simple interest is:

Option 1: $21\frac{3}{7}$%

Option 2: $21\frac{2}{7}$%

Option 3: $21\frac{1}{7}$%

Option 4: $21\frac{5}{7}$%