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Date November Example question Marks available 6 Reference code EXN.1.AHL.TZ0.16
Level Additional Higher Level Paper Paper 1 Time zone Time zone 0
Command term Find Question number 16 Adapted from N/A

Question

The cars for a fairground ride hold four people. They arrive at the platform for loading and unloading every 30 seconds.

During the hour from 9 am the arrival of people at the ride in any interval of t minutes can be modelled by a Poisson distribution with a mean of 9t0<t<60.

When the 9 am car leaves there is no one in the queue to get on the ride.

Shunsuke arrives at 9.01 am.

Find the probability that more than 7 people arrive at the ride before Shunsuke.

[2]
a.

Find the probability there will be space for him on the 9.01 car.

[6]
b.

Markscheme

* This sample question was produced by experienced DP mathematics senior examiners to aid teachers in preparing for external assessment in the new MAA course. There may be minor differences in formatting compared to formal exam papers.

Let X be the number of people who arrive between 9.00 am and 9.01 am

X~Po9

PX>7=PX8         (M1)

0.676 0.67610        A1

 

[2 marks]

a.

Mean number of people arriving each 30 seconds is 4.5        (M1)

Let X1 be the number who arrive in the first 30 seconds and X2 the number who arrive in the second 30 seconds.

P(Shunsuke will be able to get on the ride)

=PX14×PX23+PX1=5×PX22+PX1=6×PX21+PX1=7×PX2=0        M1M1

 

Note: M1 for first term, M1 for any of the other terms.

 

null        (A1)(A1)

 

Note: (A1) for one correct value, (A1)(A1) for four correct values.

 

=0.221 0.220531        A1

 

[6 marks]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Topic 4—Statistics and probability » AHL 4.17—Poisson distribution
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Topic 4—Statistics and probability

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