Correct Answer - Option 4 : 50%

**Given:**

Amount = 5P

Time = 8 years

**Formula used:**

A = P + S.I.

S.I. = PRT/100

Where, P = Principal, S.I. = Simple interest

A = Amount, R = Rate of interest, T = Time

**Calculation:**

A = P + S.I.

⇒ 5P = P + S.I.

⇒ S.I. = 4P ---(1)

As we know that, S.I. = PRT/100

From equation (1), we can write

⇒ 4P = (P × R × 8)/100

⇒ R = 50%

**∴ The rate percent is 50%.**