---
id: 699c8e045ee7cb94ed2322dd
title: "Challenge 222: Equinox Shadows"
challengeType: 28
dashedName: challenge-222
---

# --description--

Today is the equinox, when the sun is directly above the equator and perfectly overhead at noon. Given a time, determine the shadow cast by a 4-foot vertical pole.

- The time will be a string in `"HH:MM"` 24-hour format (for example, `"15:00"` is 3pm).
- You will only be given a time in 30 minute increments.

Rules:

- The sun rises at 6am directly `"east"`, and sets at 6pm directly `"west"`.
- A shadow always points opposite the sun.
- The shadow's length (in feet) is the number of hours away from noon, cubed.
- There is no shadow before sunrise (before 6am), after sunset (6pm or later), or at noon.

Return:

- If a shadow exists, return `"(length)ft (direction)"`. For example, `"8ft west"`.
- Otherwise, return `"No shadow"`.

For example, given `"10:00"`, return `"8ft west"` because 10am is 2 hours from noon, so 2<sup>3</sup> = 8 feet, and the shadow points west because the sun is in the east at 10am.

# --hints--

`getShadow("10:00")` should return `"8ft west"`.

```js
assert.equal(getShadow("10:00"), "8ft west");
```

`getShadow("15:00")` should return `"27ft east"`.

```js
assert.equal(getShadow("15:00"), "27ft east");
```

`getShadow("12:00")` should return `"No shadow"`.

```js
assert.equal(getShadow("12:00"), "No shadow");
```

`getShadow("17:30")` should return `"166.375ft east"`.

```js
assert.equal(getShadow("17:30"), "166.375ft east");
```

`getShadow("05:00")` should return `"No shadow"`.

```js
assert.equal(getShadow("05:00"), "No shadow");
```

`getShadow("06:00")` should return `"216ft west"`.

```js
assert.equal(getShadow("06:00"), "216ft west");
```

`getShadow("18:00")` should return `"No shadow"`.

```js
assert.equal(getShadow("18:00"), "No shadow");
```

`getShadow("07:30")` should return `"91.125ft west"`.

```js
assert.equal(getShadow("07:30"), "91.125ft west");
```

`getShadow("00:00")` should return `"No shadow"`.

```js
assert.equal(getShadow("00:00"), "No shadow");
```

# --seed--

## --seed-contents--

```js
function getShadow(time) {

  return time;
}
```

# --solutions--

```js
function getShadow(time) {
  const [hourStr, minuteStr] = time.split(":");
  const hours = Number(hourStr);
  const minutes = Number(minuteStr);
  const timeInHours = hours + minutes / 60;

  if (timeInHours < 6 || timeInHours >= 18 || timeInHours === 12) {
    return "No shadow";
  }

  const hoursFromNoon = Math.abs(12 - timeInHours);
  const length = Math.pow(hoursFromNoon, 3);
  const direction = timeInHours < 12 ? "west" : "east";

  return `${length}ft ${direction}`;
}
```