240, 234, 228, 214, 196, 170
Find the wrong number in the given series.

The correct option is 228.

To find the wrong number in the given number series, let us analyze the differences between consecutive terms in the sequence:

Series: 240, 234, 228, 214, 196, 170

Let us look at the differences starting from the end of the series or calculate the step-by-step reduction between adjacent numbers:

$196-170=26$

$214-196=18$

Notice the pattern in the differences of the terms:
The difference between 196 and 170 is 26.
The difference between 214 and 196 is 18 (which is 26 - 8).

If we follow this pattern of increasing the subtracted difference by 8 as we go backwards (or reducing the difference by 8 as we go left-to-right):

- Difference between 3rd term and 4th term (214) should be:
$18+8=26$... wait, following the forward sequence:

Let us establish the pattern from left to right (decreasing differences):
1st step reduction: $240-6=234$
If the pattern of differences is a sequence of numbers decreasing by specific increments:
Differences should be: 6, 10, 14, 18, 26?

Let us test the differences from right to left:
26, 18, 12, 6, 6?

Alternatively, look at the differences between adjacent terms:
$240-234=6$
$234-222=12$ (if 228 were 222)
$222-214=8$?

Let me check the difference sequence: 6, 12, 18, 26?
Let us check: $6\times 1=6$, $6\times 2=12$, $18$, $26$...
Wait, if the differences are multiples of consecutive even numbers or follows an AP:
Differences between successive terms:
$240-6=234$
$234-10=224$
$224-10=214$ (no)

Let's re-examine: $240-234=6$
$234-220=14$
$220-214=6$

Consider the logic where 228 is replaced by 224:
$240-6=234$ (difference = 6)
$234-10=224$ (difference = 10)
$224-10=214$ (no)

Consider replacing 228 with 222:
$240-234=6$
$234-222=12$
$222-214=8$
$214-196=18$
$196-170=26$

Look at the double differences of 6, 12, 18, 26:
Wait: 6, 10, 14, 18, 26?
If differences are: $\mathrm{6,\; 10,\; 14,\; 18,\; 26}$ -- wait: $\mathrm{26\; -\; 18\; =\; 8}$, $\mathrm{18\; -\; 14\; =\; 4}$, $\mathrm{14\; -\; 10\; =\; 4}$, $\mathrm{10\; -\; 6\; =\; 4}$.
If 26 is replaced? But 26 is fixed by 196 - 170 = 26.

Let us check the pattern of differences:
$240-234=6=2^2+2$
$234-228=6$ (Actual difference)
$228-214=14$ (Actual difference)
$214-196=18=4^2+2$
$196-170=26=5^2+1$? No, $5^2+\mathrm{1\; =\; 26}$.

Look at prime numbers or $n^2+n$ / $n^2-n$:
$26=5^2+1$
$18=4^2+2$
$12=3^2+3$
$8=2^2+4$
$6=1^2+5$

If the correct differences are 6, 10, 14, 18, 26? Or 6, 12, 18, 24, 30?
If differences are 6, 10, 14, 18, 26, replacing 228 with 224:
$240-6=234$
$234-10=224$
$224-14=210$ (doesn't match 214).

If replacing 228 with 224 with differences 6, 10, 18, 26? No.
If replacing 228 with 226:
$240-234=6$
$234-226=8$
$226-214=12$
$214-196=18$
$196-170=26$

Now check the differences: 6, 8, 12, 18, 26.
Second differences:
$8-6=2$
$12-8=4$
$18-12=6$
$26-18=8$

This gives a perfectly clear pattern in the second differences: 2, 4, 6, 8!

Let us verify step-by-step with this pattern:
1. First difference: $6$
2. Second difference: $6+2=8$
3. Third difference: $8+4=12$
4. Fourth difference: $12+6=18$
5. Fifth difference: $18+8=26$

Applying these first differences to subtract consecutively from 240:
- $240-6=234$
- $234-8=226$ (instead of 228)
- $226-12=214$
- $214-18=196$
- $196-26=170$

Thus, the number 228 is incorrect and should be replaced by 226 to complete the series properly.