Correct Answer - Option 1 : 6400

**Given:**

Amount in 2 years = Rs.291600

Amount in 3 years = Rs.314928

**Formula:**

Let P = Principal, R = rate of interest and N = time period

Compound interest = P(1 + R/100)^{n} - P

Amount = P(1 + R/100)^{n}

Simple interest = PNR/100

**Calculation:**

⇒ 291600 = P(1 + R/100)^{2}

⇒ 314928 = P(1 + R/100)^{3}

⇒ 1.08 = (1 + R/100)

⇒ R = 8%

Rate of interest is 8% per annum.

Then,

Simple interest = 40000 × 8 × 2/100 = Rs.6400

**∴ simple interest on Rs.40000 at the same rate for 2 years is Rs.6400.**