Series and Odd Man out Practice Test 1

Concept:In a number series, alternating positions often follow separate patterns.Explanation:Split the series into odd and even positions.Odd positions: $5, 10, 15, 30$.Even positions: $1, 2.5, 5, 10$.If the odd positions form an arithmetic progression, they should be $5, 10, 15, 20$ with a common difference of $5$.Thus $30$ is the wrong term; it should be $20$.Now, the even positions are obtained by dividing the odd positions by $5, 4, 3, 2$ respectively.Verify: $5/5 = 1$, $10/4 = 2.5$, $15/3 = 5$, $20/2 = 10$.These match the given even positions exactly.So the pattern is consistent if $30$ is replaced by $20$.Answer:The odd man out is $30$.Option B.