freeCodeCamp

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id	challengeType	title	forumTopicId
5900f3b61000cf542c50fec8	5	Problem 73: Counting fractions in a range	302186

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?

Instructions

Tests

tests:
  - text: <code>countingFractionsInARange()</code> should return a number.
    testString: assert(typeof countingFractionsInARange() === 'number');
  - text: <code>countingFractionsInARange()</code> should return 7295372.
    testString: assert.strictEqual(countingFractionsInARange(), 7295372);

Challenge Seed

function countingFractionsInARange() {

  return true;
}

countingFractionsInARange();

Solution

// solution required

1.5 KiB Raw Blame History