The average of a set of 18 consecutive integers is 22.5. What is the largest integer in the set ?
Answer & explanation
Correct answer: option 3
Let the 1st integer be x
18th integer = x + 17
Sum of 18 terms = \(\frac{18 × ( x + x + 17)}{2 × 18}\) = \(\frac{2x + 7}{2}\)
⇒ \(\frac{2x + 17}{2}\) = 22.5
⇒ x = 14
Largest number = x + 17 = 31