Math Problem Statement
If a collection of pencils is placed in rows of 3, there are 2 pencils left; if placed in rows of 5, there are 2 left; and if placed in rows of 7, there are 2 left. What is the smallest possible number of pencils in the collection?
Solution
To solve this problem, we are looking for the smallest positive integer that satisfies the following conditions:
Each of these conditions states that if the pencils are divided into rows of 3, 5, or 7, there are always 2 pencils left over. This means must be divisible by 3, 5, and 7.
Step 1: Rewrite the Problem
Since , , and , we can rewrite these congruences as: for integers , , and .
Step 2: Reduce to a Common Congruence
Since must be divisible by 3, 5, and 7, the smallest such number that meets these criteria is the least common multiple (LCM) of 3, 5, and 7.
The LCM of 3, 5, and 7 is: [ \text{LCM}(3, 5
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Math Problem Analysis
Mathematical Concepts
Modular Arithmetic
Least Common Multiple (LCM)
Number Theory
Formulas
N ≡ 2 (mod 3)
N ≡ 2 (mod 5)
N ≡ 2 (mod 7)
Theorems
Chinese Remainder Theorem
Suitable Grade Level
Grades 8-10
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