#### Introduction

Now that you have a basic understanding of the building blocks that make up JavaScript you are going to use them in problem-solving.

1. Make a function that takes a string and returns that string reversed.

Example

Input: "Hello World"
Output: "dlroW olleH"

``````let reverseStr = function(str) {

}
``````

1. Make a function that takes a string and returns true if the string could be a number else return false.

Example

Input: "3"
Output: true

Input: "three"
Output: false

``````let isNum = function(str) {

}
``````

1. Make a function that takes a number and returns true if the number is even else return false.

Example

Input: 4
Output: true

Input: 3
Output: false

``````let isEven = function(num) {

}
``````

1. Make a function that takes an array and returns the average of the array.

Example

Input: [1, 2, 3]
Output: 2

Input: [5, -10, 10, 20]
Output: 6.25

``````let averageArray = function(arr) {

}
``````

1. Make a function that takes two arrays and returns a single array of the items from the arrays added alternatingly.

Example

Input: ["a", "b", "c"] and [1, 2, 3]
Output: ["a", 1, "b", 2, "c", 3]

``````let combineArrays = function(arr1, arr2) {

}
``````