Math Problem Statement
Suppose sum of two smallest positive divisors of an integer N is 6, while the sum of the two largest positive divisors of N is 858. What is the sum of the digits of N?
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13
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15
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17
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19
Solution
Let's analyze the given conditions step by step.
Step 1: Understanding the problem
- Condition 1: The sum of the two smallest positive divisors of is 6.
- Condition 2: The sum of the two largest positive divisors of is 858.
- We need to find the sum of the digits of .
Step 2: Determine the smallest divisors
The smallest positive divisor of any integer is always 1. Let the second smallest divisor be . Therefore: Thus, the two smallest divisors are 1 and 5.
Step 3: Determine the form of
Since 5 is a divisor of , must be a multiple of 5.
Step 4: Determine the largest divisors
The largest divisor of any number is the number itself, . Let the second largest divisor be , where is another divisor of . According to the problem: Rewriting the equation: Thus,
Step 5: Testing divisors
To solve for , we need to find suitable such that is a multiple of 5. Testing values of :
- For : Thus, .
Step 6: Verify the conditions
- Smallest divisors: 1 and 5 (sum is 6).
- Largest divisors: 715 and (sum is 858).
Both conditions are satisfied.
Step 7: Sum the digits of
The sum of the digits of is:
Answer
The sum of the digits of is:
Correct Option:
01) 13
Would you like further details on any step, or have any questions?
Relative Questions:
- What is the importance of divisors in number theory?
- How can we systematically find all divisors of a number?
- Why is 1 always considered the smallest divisor of any integer?
- How does factoring help in solving divisor-related problems?
- Can the problem be solved using a different approach?
Tip:
When solving problems involving divisors, always consider both small and large divisors, as their relationships often reveal useful patterns.
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Math Problem Analysis
Mathematical Concepts
Number Theory
Divisors
Multiples
Formulas
Sum of two smallest divisors: 1 + d = 6
Sum of two largest divisors: N + (N/d') = 858
Sum of digits formula
Theorems
Basic divisor theorem
Divisibility rules
Suitable Grade Level
Grades 9-12