In following question, a number series is given with one term missing. Choose correct alternative
2, 6, 12, 20, 30, 42, 56, x
2, 6, 12, 20, 30, 42, 56,
85, 78, 65, 40, 56, x
3, 6, 29, 258, ......
90, 180, 12, 50, 100, 200, , 3, 50, 4, 25, 2, 6, 30, 3