7/25/2019 Chapter 7 Probability Question

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Mathematic Form 4

Chapter 7: Probability

Question 1:

A box contains 5 pink marbles and 21 yellow marbles. Sharon puts another 4 pinkmarbles and 1 yellow marble inside the box. A marble is chosen at random from thebox. What is the probability that a pink marble is chosen

Question 2:!n a "roup of #$ prefects% 25 are "irls. &hen 1$ boys lea'e the "roup. !f a prefect ischosen at random from the "roup% state the probability that the prefect chosen is a boy.

Question 3:($ people ha'e taken part in a sin"in" contest. !f a person is chosen at random from allthe contestants% the probability of "ettin" a male contestant is #)15. !f there are 12males and * females who did not +ualify to the second round% find the probability that amale is chosen from the second round contestants.

7/25/2019 Chapter 7 Probability Question

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Question 4:,ohn has a collection of stamps from &hailand% !ndonesia and Sin"apore. -e picks onestamp at random. &he probability of pickin" a &hailand stamp is 1)5 and the probabilityof pickin" an !ndonesia stamp is #)15. ,ohn has 2$ Sin"apore stamps. alculate thetotal number of stamps in his collection.

Question 5:A box contains *( "reen erasers and a number of red erasers. !f an eraser is pickedrandomly from the box% the probability of pickin" a red eraser is 5)# . /ind the number ofred erasers.

Question 6:A box contains blue marbles and "reen marbles. A marble is picked at random from thebox. &he probability of pickin" a blue marble is ()11. !f there are *$ "reen marbles in thebox% how many blue marbles are there in the box