A man donates 10% of his monthly net earnings to his church. If it amounts to N4,500, what is his net monthly income?

1. Analyze the question

We are given that 10% of a man's total net monthly income is equal to N4,500. We need to find the total monthly income (100%).

2. Explain the concept

This is a basic percentage problem. If we let the total monthly income be represented by $x$, the problem states that: $10\% \text{ of } x = 4,500$

In mathematics, "of" means multiplication, and percentage means "per hundred". So, we can write the equation as: $\frac{10}{100} \times x = 4,500$

3. Show the solution

• Step 1: Set up the equation. $0.10 \times x = 4,500$

• Step 2: Isolate $x$ by dividing both sides by 0.10. $x = \frac{4,500}{0.10}$

• Step 3: Perform the division. Dividing by 0.10 is the same as multiplying by 10. $x = 4,500 \times 10$ $x = 45,000$

The man's net monthly income is N45,000.

4. Identify the answer

Comparing our result to the given options: A. N40,500 B. N45,000 C. N52,500 D. N62,000

The correct option is B.

5. Tip

When dealing with percentages like 10%, you don't always need a complex formula. Just remember that 10% is simply the total divided by 10. Therefore, to find the total, just multiply the given amount by 10. If the question had said 20%, you would divide the amount by 20 and multiply by 100 (or simply multiply by 5). This mental math shortcut saves time during JAMB exams!