In a certain town some people were affected by a ’flu’ epidemic. In the first month 20% of the population contracted the flu whilst 80% were healthy. In the following month 20% of the sick people recovered and 20% of the healthy people contracted the disease. What fraction of the population is healthy at the end of the second month?
Jatin was trying to tessellate regular pentagons. He managed the following figure.
The size of angle ‘a’ is:
how do we do this one?