Binomial distribution — Smaller flight

Question

Seats 100, show-up probability 0.9, allow at most 5% chance of overflow. Outline the normal approximation inequality for tickets .

This practice question was inspired by Question 14(d) in the 2022 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.

Set up the solution: identify the random variable and its parameters before using the matching probability formula., need .
State the final answer clearly in the form the question requested. (one-sided 95%).

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

Verification: Same structure with new parameters.

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