A class has 39 pupils. One pupil comes to school with influenza…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A class has pupils. One pupil comes to school with influenza. Each of the other pupils has a % chance of catching it from the ill pupil. How many pupils are expected to catch it? How many pupils are expected to be ill in all?
Need a reminder? The key ideaShow
Infectious diseases are caused by viruses, bacteria, fungi, protozoa and worms. They spread through the air, water and food, contact and blood, from mother to child, and by vectors such as the female Anopheles mosquito and the housefly. The organ where the microbe settles decides the signs: the lungs, the liver or the brain.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. New cases. pupils are expected to catch it.
Step 2. In all. Add the first ill pupil: pupils.
Answer: new cases, and ill pupils in all. A real class gives a whole number, and it changes from one outbreak to another.
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