The next number in 5, 10, 15, 20, ... is:

## The reasoning This is an **arithmetic sequence** (also called arithmetic progression or A.P.). Look at the pattern: - From 5 to 10: we add **5** - From 10 to 15: we add **5** - From 15 to 20: we add **5** The **common difference** is 5. So the next term = 20 + 5 = **25**. The general formula is: **Next term = Last term + Common difference** ## Why the wrong options tempt you **Option A (22):** You might think "20 + 2 = 22" if you rushed and didn't spot the consistent pattern. Don't guess randomly! **Option C (30):** This looks tempting if you accidentally doubled the common difference (5 × 2 = 10), then added 20 + 10 = 30. Classic calculation slip under exam pressure. **Option D (24):** Maybe you thought "just add 4" without checking the actual pattern. Always verify the difference between *all* consecutive terms. ## Quick takeaway **In arithmetic sequences, find what you're CONSISTENTLY adding (or subtracting) between terms—that's your common difference, and it never changes.**