---
id: 5900f48a1000cf542c50ff9d
challengeType: 5
title: 'Problem 286: Scoring probabilities'
---
## Description
Barbara is a mathematician and a basketball player. She has found that the probability of scoring a point when shooting from a distance x is exactly (1 - x/q), where q is a real constant greater than 50.
During each practice run, she takes shots from distances x = 1, x = 2, ..., x = 50 and, according to her records, she has precisely a 2 % chance to score a total of exactly 20 points.
Find q and give your answer rounded to 10 decimal places.
## Instructions
## Tests
```yml
tests:
- text: euler286() should return 52.6494571953.
testString: 'assert.strictEqual(euler286(), 52.6494571953, "euler286() should return 52.6494571953.");'
```
## Challenge Seed
```js
function euler286() {
// Good luck!
return true;
}
euler286();
```