A box contains 5 red, 7 blue, and 8 green marbles. If a marble is drawn at random, what is the probability it is not green?

["Title: Probability of Not Drawing a Green Marble: A Simple Guide", "Meta Description: Learn how to calculate the probability of drawing a marble that is not green from a box containing 5 red, 7 blue, and 8 green marbles. Find the exact chance and practical explanation.", "---", "### Introduction", "Probability questions are essential in everyday decision-making and data analysis, but they can seem tricky at first glance. One common scenario involves drawing marbles from a jar—a classic probability exercise that helps build core math skills. In this article, we’ll explore a straightforward probability problem: What is the probability that a randomly drawn marble is not green, given that a box contains 5 red, 7 blue, and 8 green marbles?", "---", "### Understanding the Problem", "We start with a box holding:", "- 5 red marbles\n- 7 blue marbles\n- 8 green marbles", "Total number of marbles:\n(5 + 7 + 8 = 20) marbles", "The question asks: What is the probability that a randomly drawn marble is NOT green?", "---", "### Step-by-Step Calculation", "1. Find the number of marbles that are not green:\n Total marbles = 20\n Green marbles = 8\n Non-green marbles = Red + Blue = (5 + 7 = 12)", "2. Probability formula:\n Probability of an event =\n [\n P(\ ext{event}) = \frac{\ ext{Number of favorable outcomes}}{\ ext{Total number of outcomes}}\n ]", "3. Apply values:\n [\n P(\ ext{not green}) = \frac{12}{20} = \frac{3}{5} = 0.6\n ]", "So, the probability of drawing a marble that is not green is 60%.", "---", "### Probability in Percentage and Fraction", "- Fraction: (\frac{3}{5})\n- Decimal: 0.6\n- Percentage: (0.6 \ imes 100 = 60%)", "---", "### Why This Matters", "Understanding probabilities helps in various fields—from gambling and statistics to science and decision theory. In the case of colored marbles, this simple setup illustrates foundational probability concepts:", "- Total outcomes\n- Favorable outcomes\n- Complementary probabilities", "Note: The probability of not drawing a green marble is the complement of drawing a green marble, which is:\n[\nP(\ ext{not green}) = 1 - P(\ ext{green}) = 1 - \frac{8}{20} = \frac{12}{20} = \frac{3}{5}\n]", "---", "### Practical Tips", "- Always count total items and individual subgroups correctly.\n- Use fractions, decimals, and percentages interchangeably for better understanding.\n- Remember, "not green" includes red and blue only—so add red and blue marbles.\n- This concept applies to more complex probability problems involving color, size, or other categories.", "---", "### Conclusion", "Calculating the probability of drawing a marble that is not green is simple once you break it down: count non-green marbles, divide by total marbles, and interpret the result. From 5 red, 7 blue, and 8 green marbles, the chance of picking a non-green marble is 60%—a clear, actionable insight rooted in basic probability.", "Whether for a classroom lesson, a study guide, or just curiosity, mastering such problems builds confidence in handling statistical reasoning daily.", "---", "Keywords: probability of not green marble, marbles probability calculation, 5 red 7 blue 8 green marbles, not green probability, probability explanation, probability for beginners, how to calculate probability", "Related Articles:\n- Probability quiz: What if colors were removed?\n- How to find probability using fraction-to-decimal conversion\n- Marvelous uses of probability in everyday life", "---", "Make probability simpler—one marble at a time!"]