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);

function countingFractionsInARange() {

  return true;
}

countingFractionsInARange();

// solution required