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?

• 20 student passed both two test
  40 student passed only 1st test
  20 student passed only 2nd test
  so 100-(20+40+20)=20 student failed in both sub
  so ans is 20%
• 9 years agoHelpfull: Yes(13) No(4)
• P(A*&B*)=1-p(A or B)=1-(0.4+0.6-0.2)=0.2
• 9 years agoHelpfull: Yes(4) No(0)
• p(test1) = 60/100
  p(test2)= 40/100
  probability of students passed in both test (ie) p(test1 n test2)= 20/100=2/10
  they asked, probability of students failed in both tests so
  =1 - p(test1 n test2)
  =1-(2/10)=8/10=4/5..
• 9 years agoHelpfull: Yes(2) No(4)
• total students failed in both= 100-(60+40-20)
  =20
  required probability=.2
• 9 years agoHelpfull: Yes(1) No(0)
• Total student is 100 =n(AUB)
  60 students passed in 1st test=n(A)
  40 students passed in 2nd test=n(B)
  20 students passed both 2 tests=n(AUB)
  
  n(AUB)=n(A)+n(B)-n(A intersection B)
  
  100-20=60+40-n(A intersection B)
  
  80=100-n(A intersection B)
  
  n(A intersection B)=100-80
  
  n(A intersection B)=20///
  20 students are failed in both test
  
  
• 9 years agoHelpfull: Yes(1) No(1)
• P(A*&B*)=1-p(A or B)=1-(0.4+0.2-0.2)=39/40
  Use Venn diagram.....
  Here * means "not"
• 9 years agoHelpfull: Yes(0) No(1)
• ans is 20/100=1/5=0.2
• 9 years agoHelpfull: Yes(0) No(0)
• only passed in t1=40 ,not passed in t1=40
  only passed in t2=20,not passed in t2=60
  passed in both =20
  so max no of student who failed in both will be =40
  so prob=40/100=.4
• 9 years agoHelpfull: Yes(0) No(0)
• 1/5 as no. of student faild in both the subject is equal to 20(100-(40+20)).
• 9 years agoHelpfull: Yes(0) No(0)