1.2 KiB
1.2 KiB
| id | title | challengeType | forumTopicId | dashedName |
|---|---|---|---|---|
| 5900f3b31000cf542c50fec6 | Problem 71: Ordered fractions | 5 | 302184 | problem-71-ordered-fractions |
--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 2/5 is the fraction immediately to the left of 3/7.
By listing the set of reduced proper fractions for d ≤ 1,000,000 in ascending order of size, find the numerator of the fraction immediately to the left of 3/7.
--hints--
orderedFractions() should return a number.
assert(typeof orderedFractions() === 'number');
orderedFractions() should return 428570.
assert.strictEqual(orderedFractions(), 428570);
--seed--
--seed-contents--
function orderedFractions() {
return true;
}
orderedFractions();
--solutions--
// solution required