The simple interest on ₦8550 for 3 years at x% per annum is ₦4890. Calculate the value of x to the nearest whole number.

Analysis

To solve this problem, we need to use the standard formula for Simple Interest. We are given the principal, the time, and the interest earned, and we need to find the rate ($x$).

Concept

The formula for Simple Interest ($I$) is:

Where:

• $I$ = Simple Interest (₦4890)
• $P$ = Principal (₦8550)
• $R$ = Rate ($x$)
• $T$ = Time (3 years)

Step-by-Step Solution

1. Substitute the given values into the formula: $$4890 = \frac{8550 \times x \times 3}{100}$$

2. Simplify the right side: $$4890 = \frac{25650 \times x}{100}$$ $$4890 = 256.5 \times x$$

3. Solve for $x$: $$x = \frac{4890}{256.5}$$ $$x \approx 19.064$$

4. Round to the nearest whole number: Since 19.064 is closer to 19 than 20, the value of $x$ to the nearest whole number is 19%.

Conclusion

Comparing our result to the options provided, the correct value is 19%.

Exam Tip

When dealing with "Simple Interest" questions in JAMB, always write out your variables ($P, R, T, I$) first. It prevents you from accidentally swapping the Principal and the Interest, which is a common mistake students make under exam pressure.