100 students appeared in 2 tests.60 students passed 1st test. 40 students passed in the 2nd test. 20 students passed in both 1 and 2 tests. what is the probability of the students who failed in both tests?  Choose the correct answer:
A) 10%  B) 15%  C) 20%  D) 25%  E) 30%
20 student passed both two test   40 student passed only 1st test   20 student passed only 2nd test   so  100-(20+40+20)= 
<gadget id="calculator"> 100-(20+40+20)</gadget>
<output>20</output>
20 student failed in both sub   so ans is 20%   ANSWER:20%
<result>C</result>
100 students appeared in 2 tests.60 students passed 1st test. 40 students passed in the 2nd test. 20 students passed in both 1 and 2 tests. what is the probability of the students who failed in both tests?