GED Math : Probability

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #51 : Probability

There are 12 marbles in a box. There are 5 blue, 2 green, 3 yellow, and 2 red. Two marbles are selected, WITH replacement. What is the probability of selecting one red and one yellow?

Possible Answers:

Correct answer:

Explanation:

You can select red and yellow in one of two ways. That is  OR .

It is key, in this problem, to recall that the selection is WITH replacement.

If we add the two probabilities, we get 

.

Example Question #52 : Probability

What is the probability of selecting a king from a deck of cards, putting it aside, and then selecting an ace?

Possible Answers:

Correct answer:

Explanation:

This question involves probability WITHOUT replacement.

In a regular deck of cards, there are 52 cards, with 4 kings. The probability of selecting a king is . Once that card is out of the deck, there are 51 cards left. There are 4 aces out of 51 cards. The probability of selecting an ace out of 51 cards is .

The probability of selecting a kind AND an ace is 

Example Question #51 : Statistics

Two regular 6-sided dice are thrown. What is the probability of rolling a sum of 8?

Possible Answers:

Correct answer:

Explanation:

There are 36 equal outcomes when rolling two dice. The outcomes which fit the criteria of a "sum of 8"  are . The are 5 such outcomes.

The probability of rolling a sum of 8 is .

Example Question #54 : Probability

How many different ice cream cones can be made using one of each of the following:

Flavor: Vanilla, Chocolate, Strawberry, Cookie Dough

Topping: Rainbow Sprinkles, Chocolate Sprinkles, Almonds, Chocolate Chips, Peanut Butter Cups

Cone Type: Waffle, Sugar

Possible Answers:

Correct answer:

Explanation:

This question calls for the use of the counting principle. The counting principle has one multiply the number of options in each category. In this case, there are 4 options for flavors, 5 options for toppings, and 2 options for cone type.

So, 

There are 40 different ice cream cones to be made using one in each category.

Example Question #55 : Probability

On a movie and show night, a family plans on watching two shows and one movie. Consider the following:

1) The family has five shows that they really want to see, but decide that two will work.

2) After the shows, they will choose from one of seven DVD movies that they all agree on.

How many ways can the family watch two out of the five shows AND one of the seven movies on that night?

Possible Answers:

Correct answer:

Explanation:

This employs the counting principle, much in the way one might be used to seeing.

The family has a combination of 2 out of the 5 shows AND 1 of the 7 movies.

We call the shows A, B, C, D, and E AND the movies 1,2,3,4,5,6, and 7.

1) Choosing two shows, we have {AB, AC, AD, AE, BC, BD, BE, CD, CE, DE}. The are 10 of these.

Choosing one movie, we have {1,2,3,4,5,6,7} There are 7 of these.

There are 10 "sets" of shows and 7 "sets" of movies.

Therefore, by the counting principle, the family has 10 x 7 options to choose from. There is a total of 70 options.

2) Another way is taking multiplying the combinations of shows and movies.

That is 

Example Question #52 : Statistics

A weighted coin is flipped  times.  It is weighted such that heads comes up  out of  times on average.  What is the probability that the person in question will flip all tails?

Possible Answers:

Correct answer:

Explanation:

If the weighting is  for heads, this means that it is  for tails.  Therefore, the probability of flipping  tails will be:

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