15% of 200.

**The reasoning** To find a percentage of a number, convert the percentage to a decimal and multiply: 15% = 15/100 = 0.15 So: 15% of 200 = 0.15 × 200 = **30** Or use the faster method: (15 × 200) ÷ 100 = 3000 ÷ 100 = **30** This is the **percentage principle**: "of" means multiply, and "percent" means "per hundred." **Why the wrong options tempt you** - **A) 15** — You might just write down the percentage number itself, forgetting to actually multiply by 200. - **C) 45** — A careless calculation error, maybe mixing up numbers during multiplication. - **D) 150** — This traps students who confuse percentages with fractions. You might accidentally think "15% is close to 1/2" or forget to divide by 100, doing 15 × 200 ÷ 2 instead. **Quick takeaway** To find any percentage: multiply the number by the percent, then divide by 100 — or just move the decimal two places left first (15% → 0.15), then multiply!