Update README.md

fixed typo and added link from "June 29th" to question 55

Author: gabrielsroka

README.md

@@ -2,7 +2,7 @@
 
 I post daily multiple choice JavaScript questions on my [Instagram](https://www.instagram.com/theavocoder), which I'll also post here!
 
-From basic to advanced: test how well you know JavaScript, refresh your knowledge a bit, or prepare for your coding interview! :muscle: :rocket: I update this repo weekly with new questions. Last update: <b>June 29th</b>
+From basic to advanced: test how well you know JavaScript, refresh your knowledge a bit, or prepare for your coding interview! :muscle: :rocket: I update this repo weekly with new questions. Last update: <a href=#20190629><b>June 29th</b></a>
 
 The answers are in the collapsed sections below the questions, simply click on them to expand it. Good luck :heart:
 
@@ -1659,7 +1659,7 @@ However, we created a global variable `y` when setting `y` equal to `10`. This v
 
 ---
 
-###### 55. What's the output?
+###### <a name=20190629></a>55. What's the output?
 
 ```javascript
 class Dog {
@@ -1783,7 +1783,7 @@ console.log(delete age);
 
 #### Answer: A
 
-The `delete` operator returns a boolena value: `true` on a successful deletion, else it'll return `false`. However, variables declared with the `var`, `const` or `let` keyword cannot be deleted using the `delete` operator.
+The `delete` operator returns a boolean value: `true` on a successful deletion, else it'll return `false`. However, variables declared with the `var`, `const` or `let` keyword cannot be deleted using the `delete` operator.
 
 The `name` variable was declared with a `const` keyword, so its deletion is not successful: `false` is returned. When we set `age` equal to `21`, we actually added a property called `age` to the global object. You can successfully delete properties from objects this way, also the global object, so `delete age` returns `true`.