Problem 44861. Ratio between sums of prime and non-prime numbers

Created by Jesús Zambrano

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Write a function that calculates the ratio between the sum of the prime numbers less than or equal to x, and the sum of the non-prime numbers up to the greatest prime less than or equal to x.
For example, if x = 7, then:
sum_prime = sum([2 3 5 7]) = 17
sum_non_prime = sum([1 4 6]) = 11
Therefore, the desired ratio is:
prime_ratio = sum_prime / sum_non_prime = 17 / 11

Solve

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Last Solution submitted on Sep 15, 2025

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3 Comments

Gergely Patay on 28 Jun 2019

test case #2 is not correct.

Rafael S.T. Vieira on 27 Aug 2020

The problem description should be change to "and the sum of non-prime numbers up to the greatest prime lower than x".

goc3 on 29 Sep 2020

Thank you for that clarification, @Rafael S.T. Vieira. The problem title and description have been improved, along with added test cases.

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Problem 44861. Ratio between sums of prime and non-prime numbers

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Problem 44861. Ratio between sums of prime and non-prime numbers

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Last 200 Solutions

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Problem Recent Solvers40

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