Address review comments for paths and random exercises

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: BrianY315

Sprint-2/1-key-exercises/3-paths.js

@@ -18,7 +18,7 @@ console.log(`The base part of ${filePath} is ${base}`);
 // Create a variable to store the ext part of the variable
 
 const dir = filePath.slice(0, lastSlashIndex);
-const ext = filePath.slice(filePath.lastIndexOf(".") + 1);
+const ext = filePath.slice(filePath.lastIndexOf("."));
 console.log({ dir, ext });
 
 // https://www.google.com/search?q=slice+mdn

Sprint-2/1-key-exercises/4-random.js

@@ -8,3 +8,6 @@ console.log(num);
 // Try breaking down the expression and using documentation to explain what it means
 // It will help to think about the order in which expressions are evaluated
 // Try logging the value of num and running the program several times to build an idea of what the program is doing
+// Math.random() generates a decimal from 0 up to, but not including, 1.
+// Multiplying by (maximum - minimum + 1) scales the range to 100 possible values.
+// Math.floor() removes the decimal, and adding minimum shifts the result to an integer from 1 to 100.