So, 550 is wrong and must be replaced by (320 x 2) i.e. 640.

I. 1st, 4th, 7th terms i.e. 2, 4, 9,.....

II. 2nd, 5th, 8th terms i.e. 3, 6, 12,.....

III. 3rd, 6th, 9th terms i.e. 4, 8, 16,.....

In each one of I, II and III, each term is twice the preceding term. So, 9 is wrong and must be replaced by (4 x 2) i.e. 8.

I. 11, 20, 40, 74 and II. 5, 12, 26, 54

The correct pattern in I is + 9, + 18, + 36,.....

So, 40 is wrong and must be replaced by (20 + 18) i.e. 38.

(8³-3).

So, 27 is wrong and must be replaced (3³ - 3) i.e. 24.

So, 39 is wrong and must be replaced by (15 x 2 + 1) i.e. 31.

So, 48 is wrong and must be replaced by (92 - 48) i.e. 44.

So, 45 is wrong and must be replaced by (30 + 10) i.e. 40.

So, 654 is wrong and must be replaced by (218 x 3 - 4) i.e. 650.

So, 1536 is wrong and must be replaced by (1536 + 4) i.e. 384.

So, 132 is wrong and must be replaced by (68 x 2) i.e. 136.