1.1 KiB
1.1 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f3b41000cf542c50fec7 | Problem 72: Counting fractions | 5 | 302185 | problem-72-counting-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 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?
--hints--
countingFractions()
should return a number.
assert(typeof countingFractions() === 'number');
countingFractions()
should return 303963552391.
assert.strictEqual(countingFractions(), 303963552391);
--seed--
--seed-contents--
function countingFractions() {
return true;
}
countingFractions();
--solutions--
// solution required