Using probability to determine sums and numbers

When you have a percent or fraction that represents a probability, you can use the decimal equivalent of the percent or the fraction to determine a 

In the Jefferson family, each daughter has the same number of brothers as she has sisters, and each son has twice as many sisters as he 

When you roll a die, one of the faces lies on the table, and the other five faces are showing. The face that counts, in most games, is the face on the top of the die, after it s been rolled. 

The Problem You re nearing the end of a game of Trivial Pursuit and are just three spaces away from trying for the last pie piece (for non-Pursuit people, it s the last of six categories). You shake and shake and shake your die before rolling it. What is the probability that you ll roll either a 3 or a 5 (a 5 will allow you to roll again)  

Make a listing of all the possible results of the roll and a listing of all the numbers that you want to get. With six faces on the die, there are six different possibilities 1, 2, 3, 4, 5, or 6. You want one of two different rolls 3 or 5 (although you d prefer the number 3), so you divide 2 by 6 to get about 0.3333 or 33.33 percent. 

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