A box contains 6 red marbles numbered 1 through 6 and 4 white marbles numbered from 12 through 15. Find the probability that a marble drawn is (i) white (ii) white and odd numbered (iii) even numbered (iv) red or even numbered.
given: box containing 6 red marbles numbered 1-6, 4 white marbles numbered 12-15
formula:
one marble is drawn from the given box, total possible outcomes are 10C1
therefore n(S)=10C1=10
(i) let E be the event of getting white marble
n(E)= 4C1=4
(ii) let E be the event of getting white marble with odd numbered
E= {13,15}
n(E)= 2
(iii) let E be the event of getting even numbered marble
E= {2, 4, 6, 12, 24}
n(E)= 5
(iv) let E1 be the event of getting red marble
(from (i))
Let E2 be the event of getting even numbered marble
(from (ii))
Therefore (E1ꓵ E2) = red coloured and even numbered
n (E1ꓵ E2) =3
By law of addition P(E1∪ E2) = P(E1)+P(E2)- P(E1ꓵ E2)