in an examination 80% of the boys passed in english and 85% passed in mathematics while 75% passed in both .if 45% boys failed in both,the number of boys who sat for the examination was 1)400 2) 450 3) 200. 4) 150
in an examination 80% of the boys passed in english and 85% passed in mathematics while 75% passed in both .if 45% boys failed in both,the number of boys who sat for the examination was 1)400 2) 450 3) 200. 4) 150
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percentage students that passed at least one subject is:
P(English) + P(math) - P(both) = 85% + 80% - 75% = 90%
percentage of students that failed both
100 - P(passed at least one subject)
= 100% - 90% = 10%
45 students failed both
let the total number of students be TT
T∗(10/100)
=45T∗(10/100)=45
Solving for TT we get T=450T=450 students