1.2 KiB
1.2 KiB
id, title, challengeType, forumTopicId, dashedName
| id | title | challengeType | forumTopicId | dashedName |
|---|---|---|---|---|
| 5900f3b61000cf542c50fec8 | Problem 73: Counting fractions in a range | 5 | 302186 | problem-73-counting-fractions-in-a-range |
--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 3 fractions between 1/3 and 1/2.
How many fractions lie between 1/3 and 1/2 in the sorted set of reduced proper fractions for d ≤ 12,000?
--hints--
countingFractionsInARange() should return a number.
assert(typeof countingFractionsInARange() === 'number');
countingFractionsInARange() should return 7295372.
assert.strictEqual(countingFractionsInARange(), 7295372);
--seed--
--seed-contents--
function countingFractionsInARange() {
return true;
}
countingFractionsInARange();
--solutions--
// solution required