Hello, please help me understand this error.

Here is the error: Uncaught TypeError: Cannot read property '0' of undefined at quiz.js:15

(Line 15 of my code is the line directly under my for loop with the variable answer).

When I preview the page it is asking me all three questions in the array, but then it stops working. I'm assuming it's not able to store the answers. Something to do with there being three answers perhaps?

Thank you for the help. I hope this all displays properly; this is my first question on Treehouse :)

Here is the code:

function print(message) { document.write(message); }

var questions = [ ["What's 2 times 2?", 4], ["What's 1 times 2?", 2], ["What's 3 times 2?", 6] ];

var correctAnswers = 0;

for (var i = 0; i <= questions.length; i += 1) { var answer = prompt(questions[i][0]); if (answer === questions[i][1]) { correctAnswers += 1; } }

print('You got ' + correctAnswers + ' right, good job!');