Explanation:

- In simple interest, the interest accrued is directly proportional to the time and rate.

- If a sum triples in 4 years, the final amount is 3 times the principal.

- This implies that the interest for 4 years equals 2 times the principal.

- Therefore, the rate (R) can be calculated as:

$$

\text{Interest} = \text{Principal} \times \text{Rate} \times \text{Time}

$$

$$

2P = P \times R \times 4 \Rightarrow R = \frac{1}{2} \text{ or } 50\%

$$

- To become 5 times, the interest must be 4 times the principal:

- Using the same formula:

$$

4P = P \times \frac{1}{2} \times T \Rightarrow T = 8 \text{ years}

$$

- Option 3: 8 years is the time it will take.