Math Problem Statement

The image shows a special dice with positive integers on all sides. If you multiply the numbers on opposite sides, you always get the same answer. What is the smallest possible sum of the six numbers on the dice?

Solution

To solve this problem, we need to analyze the properties of the dice and the relationships between the numbers on opposite sides.

Step 1: Understanding the dice structure

A standard dice has six sides with opposite sides summing to 7 (e.g., 1 opposite 6, 2 opposite 5, 3 opposite 4). However, in this case, we are given the condition that the product of numbers on opposite sides is always the same. Let's call this product PP.

Let the numbers on the dice be denoted as a1,a2,a3,a4,a5,a6a_1, a_2, a_3, a_4, a_5, a_6, and assume that opposite pairs of faces are:

  • a1a_1 opposite a6a_6,
  • a2a_2 opposite a5a_5,
  • a3a_3 opposite a4a_4.

According to the problem, the products of these opposite pairs are equal, meaning: a1×a6=a2×a5=a3×a4=Pa_1 \times a_6 = a_2 \times a_5 = a_3 \times a_4 = P where PP is a constant.

Step 2: Minimizing the sum

We want to minimize the sum of the six numbers on the dice: S=a1+a2+a3+a4+a5+a6S = a_1 + a_2 + a_3 + a_4 + a_5 + a_6 Given the condition a1×a6=a2×a5=a3×a4=Pa_1 \times a_6 = a_2 \times a_5 = a_3 \times a_4 = P, one possible solution is to make each product equal to the smallest square number, since equal products often lead to small sums.

Step 3: Exploring the smallest possible values

Let's try P=6P = 6 as a test case because the factors of 6 provide integers that keep the numbers small.

  • For a1×a6=6a_1 \times a_6 = 6, one pair could be a1=1a_1 = 1 and a6=6a_6 = 6,
  • For a2×a5=6a_2 \times a_5 = 6, one pair could be a2=2a_2 = 2 and a5=3a_5 = 3,
  • For a3×a4=6a_3 \times a_4 = 6, one pair could be a3=2a_3 = 2 and a4=3a_4 = 3.

The sum of these numbers is: S=1+6+2+3+2+3=17S = 1 + 6 + 2 + 3 + 2 + 3 = 17

Thus, the smallest possible sum of the numbers on the dice is 17\boxed{17}.

Would you like more details or have any questions?

Here are 5 related questions:

  1. Can the product on opposite sides of the dice be different from 6 and still minimize the sum?
  2. How would the solution change if the dice had more than 6 sides?
  3. What is the significance of choosing small factors for the product PP?
  4. Can there be more than one solution for the numbers on the dice that yield the same sum?
  5. What are the general mathematical properties of opposite faces on a fair dice?

Tip: When dealing with sums and products, always try small factor pairs first to minimize overall values.

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Math Problem Analysis

Mathematical Concepts

Number Theory
Algebra

Formulas

Product of opposite sides: a1 * a6 = a2 * a5 = a3 * a4

Theorems

Properties of dice
Optimization techniques in minimizing sums

Suitable Grade Level

Grades 9-12