At a high school, students can choose between three art electives, four history electives, and five computer electives. each student can choose two electives.

what is the approximate probability that a student chooses a computer elective and an art elective?

0.11364
0.21212
0.22727
0.42424

If one is to choose among given choices and the order is not important, we use the concept of combination. First, we calculate for the sample space or number available since there is a total number of 12 electives and a student may choose 2 out of them.                           
S = 12C2
That is "the sample space is equal to combination of 12 taken 2". The answer to this is equal to 66. 

Next, we determine the number of outcomes. The equation will be,
                        O = (5C1) x (3C1) 
That is "outcome is equal to combination of 5 taken 1 times combination of 3 taken 1". This is equal to 15. The probability is equal to,
                        P = O/S

Substituting,
                        P = (15/66) = 0.227270
The answer to this item is the third choice.