Three consecutive odd numbers — Aptitude Question
Three consecutive odd numbers: The sum of three consecutive odd numbers is 63. What is the largest of them? Answer and worked solution on CodeKairo.
- Topic: Number System
- Section: Quantitative Aptitude
- Difficulty: Easy
- Time target: 40 seconds
Question
The sum of three consecutive odd numbers is 63. What is the largest of them?
Options
- 21
- 23
- 25
- 27
Show the answer and the worked solution
Correct answer: B. 23
Worked solution
- Three consecutive odd numbers can be written as n − 2, n, n + 2; their sum is 3n.
- 3n = 63, so n = 21 and the numbers are 19, 21, 23.
- The largest is 23.
Answer: 23.
The idea
For an odd count of evenly spaced numbers, the sum divided by the count is the middle term. Avoid the algebra of x, x + 2, x + 4 whenever the count is odd.
Shortcut. Back-substitute from the options: 23 as the largest gives 19, 21, 23, which sum to 63.
Common trap. 21 — the middle number, 63 ÷ 3, given as the answer when the question asks for the largest.