freeCodeCamp/curriculum/challenges/chinese/10-coding-interview-prep/project-euler/problem-307-chip-defects.md

---
id: 5900f4a01000cf542c50ffb2
title: 'Problem 307: Chip Defects'
challengeType: 5
forumTopicId: 301961
dashedName: problem-307-chip-defects
---

# --description--

k defects are randomly distributed amongst n integrated-circuit chips produced by a factory (any number of defects may be found on a chip and each defect is independent of the other defects).

Let p(k,n) represent the probability that there is a chip with at least 3 defects. For instance p(3,7) ≈ 0.0204081633.

Find p(20 000, 1 000 000) and give your answer rounded to 10 decimal places in the form 0.abcdefghij

# --hints--

`euler307()` should return 0.7311720251.

```js
assert.strictEqual(euler307(), 0.7311720251);
```

# --seed--

## --seed-contents--

```js
function euler307() {

  return true;
}

euler307();
```

# --solutions--

```js
// solution required
```