Q1. On a gaming machine, there are three reels with ten digits 0,1,2,3,4,5,6,7,8,9 plus a star on each reel. When a coin is inserted, and the machine started, the three reels revolve independently before coming to rest.
(a) What is the probabiity of getting a particular sequence of numbers ?
(b) What is the probability of getting three stars ?
(c) What is the probability of getting the same number on each reel ?
Q2. A bag contains 6 green and 9 yellow balls. A ball is drawn at random from the bag, its colour noted and then it is replaced. The process is then repeated. What is the probability that the ball was yellow on both occasions?
Q3. A bag contains 5 red marbles and 6 purple marbles. One marble is drawn at random and not replaced. Then a
second marble is drawn at random. What is the probability that the first marble is purple and the second one is
red?
a. 6/5
b. 3/11
c. 5/6
d. 30/121
Q4. A bag contains 5 white balls and 3 red balls. Balls are drawn in succession and not replaced. Show that the probability that the first red ball will appear at the fifth draw is 3/56.
Q5. A "true-false" exam has 10 questions. Assuming that the questions are independent and that a student is guessing, find the probability that he gets 100%.
Q6. A bag contains 7 red and 3 blue balls. A ball is drawn at random from the bag. It is not replaced and a second ball is drawn. What is the probability that the ball was red on both occasions?
n/a
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Q3. A bag contains 5 red marbles and 6 purple marbles. One marble is drawn at random and not replaced. Then a
second marble is drawn at random. What is the probability that the first marble is purple and the second one is
red?
a. 6/5
b. 3/11
c. 5/6
d. 30/121
ans is 3/11
Little Star
Q2. A bag contains 6 green and 9 yellow balls. A ball is drawn at random from the bag, its colour noted and then it is replaced. The process is then repeated. What is the probability that the ball was yellow on both occasions?
ans is 9/25
Little STar
Q5. A "true-false" exam has 10 questions. Assuming that the questions are independent and that a student is guessing, find the probability that he gets 100%.
i am not sure but i think ans is (1/2)^10
Little Star
Q6. A bag contains 7 red and 3 blue balls. A ball is drawn at random from the bag. It is not replaced and a second ball is drawn. What is the probability that the ball was red on both occasions?
ans is 7/15
Little Star
Q4. A bag contains 5 white balls and 3 red balls. Balls are drawn in succession and not replaced. Show that the probability that the first red ball will appear at the fifth draw is 3/56.
ans is (5*4*3*2/(8*7*6*5)*(3/4))=3/56
Little Star
Q1. On a gaming machine, there are three reels with ten digits 0,1,2,3,4,5,6,7,8,9 plus a star on each reel. When a coin is inserted, and the machine started, the three reels revolve independently before coming to rest.
(a) What is the probabiity of getting a particular sequence of numbers ?
(b) What is the probability of getting three stars ?
ans is 1/(11*11*11)
(c) What is the probability of getting the same number on each reel ?
ans is 10/(11*11*11)
Little Star