Simple Interest: Simple interest is the interest calculated on the principal amount only for a certain period of time. It is calculated using the formula:

Simple Interest (SI) = (Principal Amount * Rate of Interest * Time Period) / 100

Given:
Principal Amount (P) = Rs 450
Rate of Interest (R) = ?
Time Period (T) = 3 years

Simple Interest (SI) = Rs 504

SI = (P * R * T) / 100

⇒ 504 = (450 * R * 3) / 100

⇒ R = 8% per annum

Now, we have to calculate the amount of Rs 615 after 3 years at the same rate of 8% per annum:

Principal Amount (P) = Rs 615
Rate of Interest (R) = 8% per annum
Time Period (T) = 3 years

Simple Interest (SI) = ?

SI = (P * R * T) / 100

⇒ SI = (615 * 8 * 3) / 100

⇒ SI = Rs 93.20

Therefore, the total amount = Principal Amount + Simple Interest = 615 + 93.20 = Rs 708.20

Hence, the answer is Option C - Rs 676.50

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