Total Engineering student (female 120 × 0.25 = 30 + male 100 × 0.20 = 20) =50
  In total   engineering passed student of (female 30 × 0.20 = 6 + male 20 × 0.20=5) = 11
  Percentage passed student 11/50 × 100= 22
   

There are 100 female students in the class, and 20% of them are Engineering students.

Now, 20% of 100 = (20/100)× 100 = 20.

Hence, the number of female engineering students in the class is 20.

Now, 25% of the female engineering students passed the final exam:

25% of 20 = (25/100)×20 = 5.

Hence, the number of female engineering students who passed is 5.

There are 120 male students in the class and 25% of them are engineering students.

Now, 25% of 120 =( 25/100)×120 = (1/4)×120 = 30.

Hence, the number of male engineering students is 30.

Now, 20% of the male engineering students passed the final exam:

20% of 30 = (20/100)×30 = 6.

Hence, the number of male engineering students who passed is 6.

Hence, the total number of engineering students who passed is:

(Female Engineering students who passed) +(Male Engineering students who passed)

 = 5 + 6 = 11

The total number of engineering students in the class is:

(Number of female engineering students) +(Number of male engineering students) = 30 + 20 = 50

Hence, the percentage of engineering students who passed is:

= (11/50) ×100

= 22%

Male = 120 ; engr ; 30
Female= 100 ; engr; 20
--------- Engr------Pass-----fail----
male----- 30-------6-------24
female----20------5--------15
total------50------11-------39
total pass % of engr. 11/50 * 100 = 22%