We have :
I: 5       27       61       122       213       340     509
II:  22       34       61         91       127     169
III:        12        27        30        36       42
IV:            15        3         6     ;       6
Clearly, the given series becomes a triangular pattern series if each term in IV: is 6.
Again, in II: 34 must be replaced by (61 – 24) i.e., 37 and 22 by (37 – 18) i.e., 19.
Thus, in the given series, 27 is wrong and must be replaced by (5 + 19) i.e., 24.