Probability of French or Spanish with set notation

[Alkatran]

Statistics, slightly urgent

7. At Uptown University, language courses are oered in French and Span-
ish. 47% of the students study French and 39% study Spanish. 22% of
the students study both French and Spanish.
(a) What percentage of the students study a language (French or
Spanish)?
(b) What is the probability that a student studies French but not
Spanish?
(c) A student is selected randomly. Are the events A=fthe student
studies Frenchg and B=fthe student studies Spanishg indepen-
dent? Why or why not?

my answers:
(a) F or S = F + S - F and S = .47 + .39 - .22 = 64%
(b) F and (not S) = F - F and S = .47 - .22 = 25%
(c) No, F*S <> 22%

I got (b) wrong. On the answer sheet (this is a practice midterm) there is:

.47-.22.25 (draw a picture of the events to see this)

Well I drew a picture and I still think it's .47 - .22, not .47 - .22*.25

 

[uart]

I got (b) wrong. On the answer sheet (this is a practice midterm) there is:
.47-.22.25 (draw a picture of the events to see this)

Hmmm, have you considered that the given answer may be a typo that is supposed to read, 47-.22 = .25 (draw a picture of the events to see this)

 

[Alkatran]

Hmmm, have you considered that the given answer may be a typo that is supposed to read, 47-.22 = .25 (draw a picture of the events to see this)

Yes, that's why I posted here to confirm.

 

[uart]

Ok then, let me confirm that I'm pretty sure that 0.25 is the correct answer. :)

 

[Alkatran]

Ok then, let me confirm that I'm pretty sure that 0.25 is the correct answer. :)

That is Excellent