please help in “PROBABILITY AND ENGINEERING STATISTICS” !?

Question by Jim: please help in “PROBABILITY AND ENGINEERING STATISTICS” !?
Describe the possible outcomes for the following experiments, and find the probabilities asked for using the equally likely outcomes definition.
a.Three fair coins are tossed simultaneously. What is the probability of obtaining at least one head?
b.A six-sided die is tossed with one through six spots on the faces. What is the probability of a 2 or a 3?
c. A numbered disk is drawn from an urn containing 10 red and 20 white disks numbered from 1 through 10 ( one red disk has a 1, one red disk has a 2, …, two white disks have a 1, two white disks have a 2. …). What is the probability of drawing a red disk? A white disk with a 7 on it?

Best answer:

Answer by Amir
a) possibility of one head is = 1x2x2=4 and overall possibilities for this three coins are 2x2x2=8 so the probability of this comes to 4/8=1/2

b)in a dice to have the chance of 2 or 3 over all posibility is 6 positions and what we want is 2 or 3 and it’s two possibilities so probability comes to 2/6=1/3

c) can’t understand the question!!

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