TestMum
← 2021 HSC Extension 1 paper Question 14(d)

Variation 2 · answer guide

Normal distribution — Compute the exam n exactly

Question

Show that the exam calculation gives before rounding.

This practice question was inspired by Question 14(d) in the 2021 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.

Step by step

  1. Set up the solution: standardise to a z-score and use the matching standard-normal probability.From , obtain .
  2. State the final answer clearly in the form the question requested., .

Common mistake: changing so many features that the new example no longer tests the same mathematical idea.

Verification: Exact ; nearest thousand is .

Any mark labels are a TestMum study aid, not an official NESA marking allocation.

← Back to 2021 HSC Extension 1 paper Question 14(d)