Variation 3 · answer guide

Binomial distribution — p=7/12 variance factor

Question

With , the product equals

This practice question was inspired by Question 8 in the 2024 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..
Match the result to the choices and state the correct option.Therefore option A is correct.

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

Verification: This is the numerator inside the SD formula for Question 8.

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