कोणती रक्कम 9 वर्षात 8% साध्या व्याजाने रु. 3 वर्षात 800 उत्पादन 9/2% प्रतिवर्ष?

Interest on Rs 800 for 3 years at 4.5% = 800 × 4.5 × 3/100 = Rs 108. The sum needed at 8% for 9 years: P × 8 × 9/100 = 108, so P = 108 × 100/72 = Rs 150.