The sum of four consecutive odd integers is 2160. The greatest of them is
2020
The sum of four consecutive odd integers is 2160. The greatest of them is
- A.
543
- B.
429
- C.
537
- D.
641
Attempted by 30 students.
Show answer & explanation
Correct answer: A
Concept
For any set of consecutive terms in arithmetic progression, the terms are evenly spaced about their mean. Four consecutive odd integers have a common difference of 2, so if their sum is S, their mean is S ÷ 4, and the four terms sit symmetrically around that mean as (mean − 3), (mean − 1), (mean + 1), (mean + 3). The greatest term is therefore mean + 3.
Application
Let the four consecutive odd integers be x, x + 2, x + 4, x + 6, where x is the smallest.
Write the sum condition: x + (x + 2) + (x + 4) + (x + 6) = 2160.
Combine like terms: 4x + 12 = 2160.
Isolate the variable: 4x = 2148, so x = 537 (the smallest term).
The question asks for the GREATEST term, which is x + 6 = 537 + 6 = 543.
Cross-check
Using the mean shortcut: mean = 2160 ÷ 4 = 540, so the four terms are 537, 539, 541, 543 and the greatest is 540 + 3 = 543. Adding back: 537 + 539 + 541 + 543 = 2160 confirms the set. The greatest of the four integers is 543.