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probalility

In a group of students, 3/4 are male. The proportion of male students who like their curry hot is 3/5
and the proportion of female students who like their curry hot is 4/5. One student is chosen at random.
(i) Find the probability that the student chosen is either female, or likes their curry hot, or is both
female and likes their curry hot.
(edited 5 years ago)
Reply 1
Moved to Maths.

What do you normally do when you're having to find the probability of event A or event B happening? And how would you find the probability of two independent events happening at once?
Original post by successrai
In a group of students, 3/4 are male. The proportion of male students who like their curry hot is 3/5
and the proportion of female students who like their curry hot is 4/5. One student is chosen at random.
(i) Find the probability that the student chosen is either female, or likes their curry hot, or is both
female and likes their curry hot.


Try filling out this table when there are x students in total, by filling in the number of students in each box, then add up the relevant boxes and divide by x to get the probability.

Probability table.PNG
i don't think 4/5 of females like their curry hot ?

:s-smilie:
Original post by Sinnoh
Moved to Maths.

What do you normally do when you're having to find the probability of event A or event B happening? And how would you find the probability of two independent events happening at once?
The two events aren't actually independent (assuming the obvious choices for A and B).

If you want to be formal, it's a definition of conditional probability you want here:

p(AB)=p(A)p(BA)p(A \cap B) = p(A) p(B | A)
(edited 5 years ago)

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