Solution Coderbyte Easy First Factorial

Title: First Factorial
Level : Easy
Description: For this challenge you will be determining the factorial for a given number.
Clue : Using the PHP language, have the function FirstFactorial(num) take the num parameter being passed and return the factorial of it (ie. if num = 4, return (4 * 3 * 2 * 1)). For the test cases, the range will be between 1 and 18.

Solution :