If 5 men finish in 10 days, 10 men in ___ days.

**The reasoning** This is about **inverse proportion** — when one quantity increases, the other decreases proportionally. Think of it this way: The total amount of work stays the same. If 5 men complete the job in 10 days, that's **50 man-days** of work (5 men × 10 days = 50 man-days). Now, if you double the workers to 10 men, they'll share the same 50 man-days of work: - 10 men × ? days = 50 man-days - ? = 50 ÷ 10 = **5 days** More workers = less time. It's like sharing garri — more people means each person gets less! **Why the wrong options tempt you** - **B (10 days)**: You might think "same days" if you forget that more workers speed things up - **C (15) & D (20)**: These suggest *more* time with *more* workers, which makes no sense — you're confusing direct and inverse relationships **Quick takeaway** In work problems: **Men × Days = Constant work**. Double the men, halve the time!