Page 75 - Math SL HB Sem 3

Statistics And Probabiliry

6-1 DEPENDENT EVENTS
-Depehdent €vents are evenls where the occurrence of one of the events does affect
the occurrence of the other event-

-I[A and B arc dependent eventq then
:
P(A then B) P(A) x P(B given that A has occurred)
rchoE--tc^)xP(DtA)

Example:
A box contains 4 red and 2 yellow tickers. Two tickets arc randomly selected, one by one
from the box, without replacement- Find the probability that:
(a) both are red
(b) the first is red and the sccond is yellow-

Example:
A hat contairs tickets with numbers 1,2,3,19,20 printed on them- If 3 tickets are drawn
from the hat, without replacemen! determihe the probabitity that all are prime numbers.

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