Question

Which is the wrong term in the given series ?

$89,78,86,80,85,82,83$

• A. 83
• B. 82
• C. 86
• D. 78

Answer 1

The correct option is C 86

The given series is $89,78,86,80,85,82,83$.
Rationale: There is no observable pattern if the series is taken as a whole.
Breaking the series into two we can write them as
$89,86,85,83---seriesI$
$78,80,82---seriesII$
In series I the difference between the numbers is $-3,-1,-2$
In series II the difference is $+2,+2$
Hence it can be concluded that the numbers int he series are incrementing or decrementing by 2.But in series I this is possible only if the the second number is 87 instead of 86.Therefore, 86 is the wrong number.
Hence, option 'C' is correct.