320 views
0 votes
0 votes
P(a) + P(b) = 0.7

P(a intersection b) = 0.2

P {( A intersection b' ) U ( A' intersection B) } = ?

1 Answer

Best answer
2 votes
2 votes

P(a)+P(b)=0.7

P(a∩b)=0.2


we know P(a∪b)=P(a)+P(b)-P(a∩b)=0.7-0.2=0.5

P{(a∩b')∪(a'∩b)}=?   // this is actually P(either a or b but not both)

which is 0.7-2*0.2=0.3    

there is another simple method too

let x=only a   y=only b   and z=both a and b

given (x+z)+(y+z)=0.7   , z=0.2

asked x+z , which is 0.7-0.4=0.3

selected by

No related questions found