Transum Software

Exam-Style Question on Probability

A mathematics exam-style question with a worked solution that can be revealed gradually

List Of Questions Exam-Style Question More Probability Questions More on this Topic

Question id: 620. This question is similar to one that appeared on a GCSE Higher paper in 2020. The use of a calculator is allowed.

A monkey comes across a box of red and green apples in the jungle. All of the apples are the same size.

Monkey and a box of apples

There are \(n\) red apples in the box.

There are 9 green apples in the box.

The monkey is going to take at random an apple from the box.

The primatologist who provided the box of apples and who is observing the monkey's behaviour suspects the monkey is colour blind. He concludes that the probability that the apple will be red is \( \dfrac{3}{7} \).

(a) Show why the probability cannot be \( \dfrac{3}{7} \).

After the monkey has taken the first apple from the box and eaten it, he is going to take at random a second apple from the box.

(b) Given that the probability that both the apples he takes will be red is \( \dfrac{2}{5} \) work out the number of red apples in the box.

You must show all your working.

The worked solutions to these exam-style questions are only available to those who have a Transum Subscription.

Subscribers can drag down the panel to reveal the solution line by line. This is a very helpful strategy for the student who does not know how to do the question but given a clue, a peep at the beginnings of a method, they may be able to make progress themselves.

This could be a great resource for a teacher using a projector or for a parent helping their child work through the solution to this question. The worked solutions also contain screen shots (where needed) of the step by step calculator procedures.

A subscription also opens up the answers to all of the other online exercises, puzzles and lesson starters on Transum Mathematics and provides an ad-free browsing experience.



Drag this panel down to reveal the solution

The exam-style questions appearing on this site are based on those set in previous examinations (or sample assessment papers for future examinations) by the major examination boards. The wording, diagrams and figures used in these questions have been changed from the originals so that students can have fresh, relevant problem solving practice even if they have previously worked through the related exam paper.

The solutions to the questions on this website are only available to those who have a Transum Subscription.


Exam-Style Questions Main Page


Search for exam-style questions containing a particular word or phrase:

To search the entire Transum website use the search box in the grey area below.


Do you have any comments about these exam-style questions? It is always useful to receive feedback and helps make this free resource even more useful for those learning Mathematics anywhere in the world. Click here to enter your comments.


©1997-2024 WWW.TRANSUM.ORG

©1997 - 2024 Transum Mathematics :: For more exam-style questions and worked solutions go to