A bag contains 5 red, 7 blue, and 8 green marbles. If a marble is drawn at random, what is the probability of drawing a blue marble?

Mon, 20 Apr 2026 12:39:22 +0000

**1. Intro – Curiosity That Drives Discovery**
Curious about chance and probability? Imagine reaching into a bag with quiet anticipation—five red, seven blue, and eight green marbles hidden within. If a marble is drawn at random, what’s the chance you’ll pull blue? This simple question isn’t just a classroom example—it’s a gateway to understanding patterns in randomness, a concept widely discussed in math communities, educational apps, and problem-solving circles across the U.S. Whether for learning, trending content, or sharpening intuition, this scenario sparks thoughtful engagement—perfect for mobile users exploring data, statistics, or probability basics. **2. Why This Question Matters Now**
Chance and probability shape everyday decisions—from sports forecasting to investment analysis, and from classroom lessons to interactive games. The structure of this marble bag—5 red, 7 blue, 8 green—is a classic example used to introduce fundamental probability principles. With growing interest in STEM, personalized learning apps, and gamified education platforms, this blank-sorting prompt remains evergreen. It reflects how simple math helps decode randomness in news trends, health data, and digital behavior—all topics actively explored by US readers today. **3. How It Actually Works**
The probability of drawing a blue marble is calculated by dividing the number of blue marbles by the total number of marbles. With 5 red, 7 blue, and 8 green, the total is 20 marbles. So, the chance of drawing blue is 7 out of 20—equivalent to 0.35, or 35%. This measurement reflects the ratio of desired outcomes to total possibilities, a core concept in probability that applies across industries and user interests in the United States. **4. Common Questions — Answered Clearly**
- **How do you calculate probability?** Divide favorable outcomes by total possible outcomes.
- **Can probabilities vary by draw method?** Yes—sampling without replacement changes probabilities across draws, but for one symmetric draw, the ratio holds.
- **Does painting or marble size affect chance?** Not if ratios remain consistent; only absolute numbers and uniformity matter.
- **What if there are more colors or different numbers?** The formula stays the same: count the target color, divide by total marbles.