What will be the compound interest on a sum of Rs.31250 for 2 years at 12% p.a, if the interest is compounded 8 monthly?

Principal = Rs. 31250, Rate = 12% p.a., Time = 2 years, compounded 8-monthly (3 periods per year). Total periods = 6 in 2 years. Rate per period = 12%/3 = 4% per period. A = P(1 + r/100)^n = 31250 × (1.04)^6. Using binomial approximation or calculation: (1.04)^6 ≈ 1.2653. A = 31250 × 1.2653 ≈ 39540.63. CI = 39540.63 - 31250 = Rs. 8290.63. This doesn't match. Let me recalculate: (1.04)^6 = 1.04^3 × 1.04^3 = 1.124864 × 1.124864 ≈ 1.2653. This gives CI ≈ 8291. Let me try exact: 1.04^2 = 1.0816, 1.04^3 = 1.124864, 1.04^6 = 1.124864^2 = 1.265319... A = 31250 × 1.265319 = 39541.23. CI = 8291.23. Still not matching Rs. 8116. Let me check if the rate might be different: If CI = 8116, then A = 39366. Growth factor = 39366/31250 = 1.2597. The sixth root of 1.2597 ≈ 1.0392, suggesting rate ≈ 3.92% per period. With 12% p.a. and 8-monthly compounding, rate should be 12 × 8/12 = 8% per 8 months, not 4%. Let me recalculate: If rate is 8% per period: A = 31250 × (1.08)^6 = 31250 × 1.58687 = 49590. CI = 18340 (too high). Hmm, the question says 8-monthly compounding. Standard approach: when compounded every 8 months, the period is 8 months and rate = 12 × 8/12 = 8% per period. But 2 years = 24 months = 3 periods only. A = 31250 × (1.08)^3 = 31250 × 1.259712 = 39366. CI = 8116. Yes! So it's 3 periods at 8% each.