docs(sprint-1): add concise answers for percentage change interpretation

Author: Tarawally

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -12,11 +12,20 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
+// 6 function calls: Line 4 (replaceAll, Number), Line 5 (replaceAll, Number), Line 10 (console.log)
 
 // b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem?
+// SyntaxError on line 5: missing comma between arguments "," and ""
+// Fix: priceAfterOneYear.replaceAll(",", "")
 
 // c) Identify all the lines that are variable reassignment statements
+// Line 4: carPrice = Number(carPrice.replaceAll(",", ""));
+// Line 5: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // d) Identify all the lines that are variable declarations
+// Line 1: let carPrice, Line 2: let priceAfterOneYear, Line 7: const priceDifference, Line 8: const percentageChange
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// Converts string with commas ("10,000") to number (10000) for mathematical calculations
+// replaceAll(",", "") removes commas, Number() converts string to number
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll