Exam-Style Question on Probability
A mathematics exam-style question with a worked solution that can be revealed gradually
Question id: 184. This question is similar to one that appeared on a GCSE Higher paper (specimen) for 2017. The use of a calculator is allowed.
Donna is in a class of 25 students, 5 of whom have a pet dog.
There are 2200 students in the school.
(a) Use this information to estimate how many students in the school have pet dogs.
(b) Luka is at a different school.
She is in a class of 28 students, 7 of whom have pet dogs.
Luka and Donna have an idea. They think "In our two classes there are 53 students, 12 of whom have a pet dog. We can use this bigger sample to improve the estimate for Donna's school."
What assumption have they made?
(c) Use this idea to estimate how many students in Donna's school have pet dogs.
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