Math Problem Statement

We have 16 cards, 4 each of red, green, yellow and blue. How many choices we have to selecting 3 out these 16 cards, satisfying that these three cards are different colors and red appears at most once.

Solution

To solve the problem, let's break it down step by step:

Step 1: Understand the Problem

You have 16 cards, with 4 each of red, green, yellow, and blue. You need to select 3 cards such that:

  1. The three cards are of different colors.
  2. The red card appears at most once.

Step 2: Consider Possible Cases

There are two possible cases to consider:

  1. Case 1: No red card is selected.
  2. Case 2: Exactly one red card is selected.

Step 3: Count the Number of Choices for Each Case

Case 1: No red card is selected

  • Since we need 3 cards of different colors, we can choose from the 3 remaining colors (green, yellow, blue).
  • The number of ways to choose 3 colors out of these 3 is exactly 1 (since all colors must be chosen).
  • From each of these 3 colors, we can pick any of the 4 available cards.
  • Therefore, the number of combinations in this case is: 4×4×4=43=644 \times 4 \times 4 = 4^3 = 64

Case 2: Exactly one red card is selected

  • We need to choose 2 other colors from the remaining 3 (green, yellow, blue).
  • The number of ways to choose 2 colors out of these 3 is (32)\binom{3}{2}.
  • From each of these 2 chosen colors, we can pick any of the 4 available cards.
  • The number of combinations in this case is: (32)×4×4×4=3×4×4=48\binom{3}{2} \times 4 \times 4 \times 4 = 3 \times 4 \times 4 = 48

Step 4: Add the Results from Both Cases

The total number of choices is the sum of the cases: 64 (Case 1)+48 (Case 2)=11264 \text{ (Case 1)} + 48 \text{ (Case 2)} = 112

Final Answer:

There are 112 different ways to select 3 cards from the 16, satisfying that the three cards are different colors and red appears at most once.


Do you want more details or have any questions? Here are some related questions you might find interesting:

  1. What if we wanted exactly two red cards?
  2. How many ways can we select 3 cards if no restrictions on colors are applied?
  3. How would the answer change if we had 5 cards of each color?
  4. What is the probability of drawing exactly one red card when choosing 3 cards at random?
  5. How many ways can we arrange 3 cards of different colors in a line?

Tip: When solving problems involving combinations and restrictions, breaking the problem into cases often simplifies the solution.

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Math Problem Analysis

Mathematical Concepts

Combinatorics
Probability
Counting Principles

Formulas

Combinations formula: C(n, k) = n! / (k! * (n - k)!)
Multiplication Principle of Counting

Theorems

Combination Theorem

Suitable Grade Level

Grades 10-12