The mean of 10, 20, 30 and 40 is:

**The reasoning** The **mean** (or average) is the sum of all values divided by how many values you have. Here's the working: - Sum = 10 + 20 + 30 + 40 = 100 - Number of values = 4 - Mean = Sum ÷ Number of values = 100 ÷ 4 = **25** Think of it like sharing ₦100 equally among 4 friends — each gets ₦25. **Why the wrong options tempt you** - **A) 20** — You might pick the second-smallest number, but that's not how mean works - **C) 30** — This is the median (middle value when arranged), not the mean. Don't confuse them! - **D) 100** — This is the sum before dividing. The trap is stopping too early — you MUST divide by the count **Quick takeaway** Mean = **Add everything, then divide by how many things** — never forget that final division step!