1. **State the problem:** It takes 8 men 10 days to build a wall. We want to find how many men are needed to build the same wall in 2 days. 2. **Formula and concept:** The amount of work done is constant. Work = Men × Days. 3. Let the number of men needed to build the wall in 2 days be $x$. 4. Using the formula for work: $$8 \times 10 = x \times 2$$ 5. Simplify the equation: $$80 = 2x$$ 6. Divide both sides by 2 to solve for $x$: $$\cancel{\frac{80}{2}} = \cancel{\frac{2x}{2}}$$ $$40 = x$$ 7. **Answer:** 40 men are needed to build the wall in 2 days.