Blabla

Question | Answer |

1 | 16/52 |

2 | 9/12 * 8/11 |

3 | 2/6 or 1/3 |

4 | 68/123 |

5 | 28/52 |

6 | 5/8 |

7 | 1/4 |

8 | 4/52 * 3/51 = 1/221 |

9 | 1/13 * 4/51 = 4/663 |

10 | 94/124 = 47/62 |

11 | 43/71 |

12 | 3/36 or 1/12 |

MAT215

Practice Questions for Section 3.2, 3.3

Solutions

1. Standard deck of cards has 52 cards, 4 of them are Kings and one King is King-Spade.

Total number of Spades in the deck is 13.

P (King OR Spade) = P (King) + P (Spade) – P (King-Spade)

P (King OR Spade) = 4/52 + 13/52 – 1/52 = 16/52

2. Probability that first ball is red is: 9/12.

When we take second ball, there are only 8 red balls in the box from 11 total.

Probability that second ball is red is: 8/11.

P (A and B) = P (A) * P(B)

P (Red, Red) = (9/12) * (8/11) = (3/4) * (8/11) = 24/44 = 6/11

3. When you roll one 6-sides, there are only two ways to have 5 or greater on the top:

it’s 5 or 6 – 2 ways. Total number of possible outcomes is 6.

P (x ≥ 5) = 2/6 = 1/3

4. 15 + 53 = 68 people like tea out of total 22 + 33 + 15 + 53 = 125

P (Like Tea) = 68/123

5. Standard deck of cards has 52 cards, half of them are red (26).

Standard deck has 4 Queens and two of them are red.

P (Red or Queen) = P (Red) + P (Queen) – P (Queen and Red) =

= 26/52 + 4/52 – 2/52 = 28/52 = 7/13

6. P (A if B) = P (A and B) / P (B)

P (overweight if person is a woman) = P (female and overweight ) / P(woman) =

= 0.25 / 0.40 = 25/40 = 5/8

7. P (overweight if person is a man) = P (male and overweight ) / P(man) =

= 0.15 / 0.60 = 15/60 = 3/12 = ¼

8. Standard deck of cards has 52 cards and 4 of them are Aces....