The simple interest earned on a principal of Rs. 1600 at the rate of 5% per annum for a period of 6 years is to be calculated. What will be the amount of simple interest earned over these 6 years?

Introduction / Context:
This is a direct application of the simple interest formula, where the learner is given principal, rate, and time, and must compute the interest. Questions of this type are fundamental for building confidence in interest calculations and appear regularly in quantitative aptitude sections of exams. Understanding this allows one to handle more complex questions involving comparisons or rate changes later on.

Given Data / Assumptions:
Principal P is Rs. 1600.
Rate of interest r is 5 percent per annum.
Time period t is 6 years.
Interest is calculated using simple interest, not compound interest.
The rate is constant for the entire period of 6 years.

Concept / Approach:
The simple interest formula is I = P * r * t / 100. Since P, r, and t are all known, we simply substitute the values and carry out the arithmetic steps. Simple interest grows linearly with time, so doubling the time doubles the interest when principal and rate are unchanged. Here we just need one clean calculation to arrive at the final interest amount.

Step-by-Step Solution:
Write the formula for simple interest: I = P * r * t / 100.Substitute P = 1600, r = 5, and t = 6.So I = 1600 * 5 * 6 / 100.First, compute 5 * 6 = 30.Thus I = 1600 * 30 / 100.Multiply 1600 by 30 to get 48000.Now divide 48000 by 100 to obtain I = 480 rupees.Hence, the simple interest earned on Rs. 1600 at 5 percent for 6 years is Rs. 480.

Verification / Alternative check:
We can think of interest per year to confirm the result. Interest for one year at 5 percent on Rs. 1600 is 1600 * 5 / 100 = 80 rupees. Since simple interest is the same each year, interest for 6 years is 6 * 80 = 480 rupees. This matches our earlier calculation using the full formula and confirms that the result is correct.

Why Other Options Are Wrong:
Rs. 2080 is much too high and might incorrectly represent the final amount instead of the interest, or a miscalculation with a higher rate.
Rs. 450, Rs. 496, and Rs. 520 are all close to the correct answer numerically but do not match exactly and arise from arithmetic mistakes or incorrect multiplication or division steps.
Because only Rs. 480 matches the correctly computed simple interest, the other choices are all incorrect.

Common Pitfalls:
Some students forget to divide by 100 after multiplying P, r, and t, which leads to large incorrect values. Others may accidentally multiply only some of the numbers or miscalculate 5 * 6. Confusing interest with amount is another issue, where learners wrongly add principal before finishing the interest calculation. Being systematic and writing each step clearly prevents these errors.

Final Answer:
The simple interest earned on Rs. 1600 at 5 percent per annum for 6 years is Rs. 480.