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Home > CCG > Chapter 1 > Lesson 1.2.1 > Problem 1-55


Probability is used to make predictions. See the Math Notes in this lesson for more details. Whenever the outcomes are equally likely, the probability in general is:

For example, if you were to reach into a bag with total shapes, four of which have right angles, and randomly pull out a shape, you could use probability to predict the chances of the shape having a right angle.

The example above shows all forms of writing probability: (read “”) is the probability as a ratio, is its decimal form, and % is its equivalent percent. What else can probability be used to predict? Analyze each of the situations below: Homework Help ✎

Use the P(success) formula above to solve parts (a-d).

  1. The historic carousel at the park has giraffes, lions, elephants, horses, monkey, unicorns, ostriches, zebras, gazelles, and even dinosaur. Eric’s niece wants for Eric to randomly pick an animal to ride. What is the probability (expressed as a percent) that Eric picks a horse, a unicorn, or a zebra?

  2. Eduardo has in his pocket $1 in pennies, $1 in nickels, and $1 in dimes. If he randomly pulls out just one coin, what is the probability that he will pull out a dime? 

  3. 1-55d Target diagram with one regular die if you roll the die just once.

  4. P(dart hitting a shaded region) if the dart is randomly thrown and hits the target at right.