Find the amount to be paid at the end of 3 years in each case:
(a) Principal = Rs. 1,200 at 12% p.a.
(b) Principal = Rs. 7,500 at 5% p.a.
(a) According to the question,
Principal (P) = Rs 1200
Rate (R) = 12 % p.a.
Time (T) = 3 years
We know that,
Simple interest (S.I) = 
Therefore,
S.I = 
= 12 × 12 × 3
= 144 × 3
= Rs 432
Hence,
Amount = Principal + S.I
= 1200 + 432
= Rs 1632
(b) According to the question,
Principal (P) = Rs 7500
Rate (R) = 5 % p.a.
Time (T) = 3 years
We know that,
Simple interest (S.I) = 
Therefore,
S.I = 
= 75 × 5 × 3
= 75 × 15
= Rs 1125
Hence,
Amount = Principal + S.I
= 7500 + 1125
= Rs 8625
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