Answer:
The number of cases prior to the increase is 50.
Step-by-step explanation:
It is given that the number of measles cases increased by 13.6% and the number of cases after increase is 57.
We need to find the number of cases prior to the increase.
Let x be the number of cases prior to the increase.
x + 13.6% of x = 57
Divide both the sides by 1.136.
Therefore the number of cases prior to the increase is 50.