Directions: One term in the number series given below is incorrect. Find out the wrong term.

25, 29, 21, 33, 17, 39, 13

The correct answer is 39.

Step-by-step explanation:

Let us analyze the pattern of differences between consecutive terms in the given number series:

25, 29, 21, 33, 17, 39, 13

The series follows an alternating addition and subtraction pattern using consecutive multiples of 4 (+4, -8, +12, -16, +20, -24, ...):

$25+4=29$

$29-8=21$

$21+12=33$

$33-16=17$

Following this rule, the next term should be obtained by adding 20 to 17:

$17+20=37$

However, the given term in the series is 39 instead of 37.

To verify, subtracting 24 from 37 gives:

$37-24=13$

This matches the final term in the series (13).

Therefore, the wrong term in the given series is 39.