Question

Find the wrongly placed number in the series:

1,3,10,21,64,129,389,777

• A. 21
• B. 64
• C. 389
• D. 777

Answer 1

Answer:

C. 389

The correct pattern is x 2 + 1, x 3 + 1, x 2 + 1, x 3 + 1,..... So, 356 is wrong and must be replaced by (129 x 3 + 1) i.e. 388.