A gumball machine has 16 green gumballs 8 red gumballs, and 6 blue gumballs. What is the probability that the next two gumballs selected will be red
Answers
Answer:
tpo = 30
Step-by-step explanation:
foc=8 of red
8 ÷30 × 22÷30
Answer:
World Translations Strategy Guide, 3rd ed
Chapter 5 - Probability Strategy
p. 98
Wording of problem:
"A miniature gumball machine contains 7 blue, 5 green, and 4 red gumballs, which are identical except for their colors. If the machine dispenses three gumballs at random, what is the probability that it dispenses one gumball of each color?"
Explanation (relevant part for my question):
"In general, when you have a symmetrical problem with multiple equivalent cases, calculate the probability of one case (often by using the domino-effect rule). Then multiply by the number of cases. Use combinatorics to calculate the number of cases, if necessary. Remember that when you use a symmetry argument, the situation must truly be symmetrical. In the case above, if you swapped the order of "red" and "green" emerging from the gumball machine, nothing would change about the problem. As a result, we can use symmetry to simplify the problem."
My question:
In spite of the explanation given in the book (and quoted above), I still don't really know what "symmetry" means when applied to probability. Does symmetry mean that each outcome has an equal chance of happening? Could you maybe give an example of a case that is not symmetrical? Thanks for your help!!
Students
Posts: 13
Joined: Thu Jun 25, 2009 4:36 pm
Step-by-step explanation: