Question

The average of five consecutive even numbers is $54$. What is the difference between the highest and lowest numbers?

• A. $5$
• B. $6$
• C. $8$
• D. $10$

Answer 1

The correct option is C $8$

Let k be the first even number. Since we know that the consecutive numbers differ by $2$, the next even number will be $k+2$, and so on.​
Let the five consecutive even numbers be​ $k,k+2,k+4,k+6,$ and $k+8$.
We can clearly see that $k$ is the lowest even number and $k+8$ is the highest even number. ​
Therefore, the difference between the highest and the lowest even number $=(k+8)–\left(k\right)=8$