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Math Applications HL Paper 1 (May 2025, TZ2)

  1. [Maximum mark: 9]

A biologist uses a wire frame to count the number of worms in a 1 m² section.

She models the number of worms found in each 1 m² section as following a Poisson distribution with mean 1.2.

(a) Find the probability of observing exactly one worm in one 1 m² section. [1]

(b) Find the probability of observing at least one worm in one 1 m² section. [1]

The biologist looks at 5 independent 1 m² sections.

(c) Find the probability of observing a total of five worms in 5 sections. [2]

(d) Find the probability of observing exactly one worm in all 5 sections. [2]

(e) Find the probability of observing at least one worm in exactly 3 of the 5 sections. [3]