1. Problem statement: Calculate the interest for 12 months at a monthly interest rate of 20% on a principal amount of 1786. 2. Formula used: The simple interest formula is $$I = P \times r \times t$$ where $I$ is interest, $P$ is principal, $r$ is rate per period, and $t$ is time periods. 3. Here, $P = 1786$, $r = 20\% = 0.20$ per month, and $t = 12$ months. 4. Calculate the interest: $$I = 1786 \times 0.20 \times 12$$ 5. Simplify: $$I = 1786 \times 2.4 = 4286.4$$ 6. Explanation: Since the interest rate is monthly, multiply by 12 to get total interest for 12 months. 7. Final answer: The interest for 12 months is $4286.4$.