Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com> Co-authored-by: Kristofer Koishigawa <scissorsneedfoodtoo@gmail.com> Co-authored-by: Beau Carnes <beaucarnes@gmail.com>
1.4 KiB
1.4 KiB
id, challengeType, isHidden, title, forumTopicId
id | challengeType | isHidden | title | forumTopicId |
---|---|---|---|---|
5900f3b41000cf542c50fec7 | 5 | false | Problem 72: Counting fractions | 302185 |
Description
Consider the fraction, n/d, where n and d are positive integers. If n<d and HCF(n,d)=1, it is called a reduced proper fraction.
If we list the set of reduced proper fractions for d ≤ 8 in ascending order of size, we get:
1/8, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 3/8, 2/5, 3/7, 1/2, 4/7, 3/5, 5/8, 2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 7/8
It can be seen that there are 21 elements in this set.
How many elements would be contained in the set of reduced proper fractions for d ≤ 1,000,000?
Instructions
Tests
tests:
- text: <code>countingFractions()</code> should return a number.
testString: assert(typeof countingFractions() === 'number');
- text: <code>countingFractions()</code> should return 303963552391.
testString: assert.strictEqual(countingFractions(), 303963552391);
Challenge Seed
function countingFractions() {
// Good luck!
return true;
}
countingFractions();
Solution
// solution required