Question

(d) Chris chooses a card at random, replaces it, then chooses a

cards she chooses has the letter M printed on it.
(e) Graham chooses a card at random and does not replace it. He continues until he chooses a card with the letter M
printed on it. Find the probability that this happens when he chooses the 3rd card.
Question 2
Percy throws a fair dice until he gets a five.
...
:
20
(a) Work out the probability that Percy gets the five on his first throw.
(b) Find the probability that he has to throw the dice exactly twice to get the five.
(c) Calculate the probability that he will have the throw the dice more than twice to get a five.​

Answer 1

Explanation:

I'm assuming you have 26 cards each with a different letter on it.

(d) Prob(Not M, Not M , M)

= 25/26 * 25*26 * 1/26

= 625/17576

or 0.036 to nearest thousand

(e) Prob(Not M, Not M, M) without replacement

= 25/26*24/25*/1/24

= 1/26

or 0.038 to nearest thousandth.

2(a)

1/6.

(b)

5/6 * 1/6

= 5/36.

(c)

5/6 * 5/6

= 25/36