Question

Difficulty: EasyBasic Probability and Counting Methods

A bookshelf contains 44 mystery novels, 66 science fiction novels, and 55 biography books. If one book is chosen at random from the bookshelf, what is the probability that the chosen book is NOT a science fiction novel?

  1. 35\frac{3}{5}Answer
  2. B
    25\frac{2}{5}
  3. C
    23\frac{2}{3}
  4. D
    32\frac{3}{2}
  5. E
    1115\frac{11}{15}

Answer

The probability that the chosen book is NOT a science fiction novel is 35\frac{3}{5}.
The correct answer is 35\frac{3}{5}. To find the probability of selecting a book that is not science fiction, divide the number of books that are not science fiction (44 mystery + 55 biography = 99) by the total number of books (4+6+5=154 + 6 + 5 = 15). This yields 915\frac{9}{15}, which simplifies to 35\frac{3}{5}.

Step-by-Step Solution

1
Find the total number of books on the shelf
Total books = 4+6+5=154 + 6 + 5 = 15
The sample space consists of all mystery, science fiction, and biography books combined.
2
Count the number of books that are NOT science fiction
Non-science fiction books = 4+5=94 + 5 = 9
The mystery novels (44) and biography books (55) are the favorable outcomes.
3
Calculate the probability and simplify the fraction
Probability = 915=35\frac{9}{15} = \frac{3}{5}
Probability is the number of favorable outcomes divided by the total number of outcomes.

Key Concept

Basic Probability of Complementary Events
Estimated Time:45s
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