7th Grade Math

= Step-by-Step Solutions begin on page R1.

Extra Practice begins on page EP2.

Example 1 For each situation, find the sample space using a tree diagram.

5. tossing a coin and spinning the spinner
   5 1

2

3

4

from the choices at the right

6. picking a number from 1 to 5 and
   choosing the color red, white, or blue


7. choosing a purple, green, black, or silver
   bike having 10, 18, 21, or 24 speeds


8. choosing a letter from the word SPACE and choosing a consonant from
   the word MATH


9. CLOTHES Jerry can buy a school T-shirt with either short sleeves or long
   sleeves in either gray or white and in small, medium, or large. Find the
   sample space for all possible T-shirts he can buy.


10. FOOD Three-course dinners can be Appetizers Entrees Desserts
    Soup
    Salad

Steak

Chicken

Fish

Carrot cake

Apple pie

made from the menu shown. Find

the sample space for a dinner

consisting of an appetizer, entrée,

and dessert.

Example 2 For each game, find the sample space. Then find the indicated probability.

11. Elba tosses a quarter, a dime, and a nickel. If tails comes up at least twice,
    Steve wins. Otherwise Elba wins. Find P(Elba wins).


12. Ming rolls a number cube, tosses a coin, and chooses a card from two
    cards marked A and B. If an even number and heads appears, Ming
    wins, no matter which card is chosen. Otherwise Lashonda wins. Find
    P(Ming wins).

1313 FAMILIES Mr. and Mrs. Romero are expecting triplets. Suppose the chance

of each child being a boy is 50% and of being a girl is 50%. Find the

probability of each event.

a. P(all three children will be boys)

b. P(at least one boy and one girl)

c. P(two boys and one girl)

d. P(at least two girls)

e. P(the first two born are boys and the last born is a girl)

14. GAMES The following is a game for two players. Counters Side 1 Side 2
    Counter 1 red blue
    Counter 2 red yellow
    Counter 3 blue yellow

• Three counters are labeled according
  to the table at the right.


• Toss the three counters.


• If exactly 2 counters match, Player 1 scores
  a point. Otherwise, Player 2 scores a point.
  Find the probability that each player scores a point.

B

Lesson 1B Probability 437

Real-World Link

The average family

size in the United

States is 2.59 people.

T

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