Worked Solutions to the 2020 HSC Mathematics Extension 1 Exam

Each year, as soon as the paper is officially published, I work through the solutions to the latest HSC exam while we wait for the official solutions to be published. You can find my complete handwritten solutions to all questions on the 2020 HSC Mathematics Advanced Exam here:


Any corrections made to the answers will be posted here. If you find what you think may be an error, please let me know!

Very soon we will upload videos of detailed explanations for all questions on this latest test. You can subscribe to our YouTube channel to be notified when they are published, or check back here!

2020 students – congrats to you for getting through this difficult year and sticking with your maths course!


My thoughts on this exam:

Even though the Extension 1 exam is a shorter exam than Advanced and Extension 2, it somehow felt longer to me than either of those. This year’s exam averaged out in difficulty in my opinion, with questions 11 and 12 well on the easier side and 13 and 14 on the much more difficult side. My favourite question may have been 13(b), as it used a lot of skills learned in Extension 1 in one 4-mark question.

Difficult combinatorics questions usually leave a little room for me to not feel absolutely certain, so if anyone has any comments on my solution to 14(a) part (iv) please let me know! I also felt uncertain about how students were meant to answer 13(c) part (ii). My approach was to integrate and consider the arbitrary constant but that didn’t feel like 3 marks. Lastly, I showed the result in 14(b) part (iii), but I didn’t use any results from parts (i) and (ii), and I was expecting them to play a part. So I am wondering if there was another way to answer this one. Let me know how you approached these particular questions, and I also welcome any comments you might have regarding your thoughts or experience with this exam. Do you think this exam was harder than Extension 2 this year? Feel free to drop a comment below or contact me via email.

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