In each of these questions a number series is given. In each series only one number is wrong. Find out the wrong number.

188, 177, 199, 166, 210, 150, 221

The correct option is 150.

Let's analyze the pattern of the given number series by examining the differences between consecutive terms:

Starting with 188:

$188-11=177$

$177+22=199$

$199-33=166$

$166+44=210$

Notice the alternating operations with increasing multiples of 11 ($-11$, $+22$, $-33$, $+44$, ...).

Following this established pattern, the next operation should subtract 55 from 210:

$210-55=155$

However, the given series has 150 instead of 155.

Let's verify the final term using 155 with the next term in the pattern ($+66$):

$155+66=221$

This matches the last term in the series (221).

Therefore, the wrong number in the series is 150 (it should be 155).