Question

The number of measles cases increased 10.2% to 58 cases this year, what was the number of cases prior to the increase? (Express your answer rounded correctly to the nearest whole number)

Answer 1

There were approximately 53 cases of measles before the increase.

Explanation:

Since there was an increase of 10.2% this means that the value we have now is the value we had prior plus the increase, in other words this is 100% of the cases before the increase plus 10.2%, so we have now 110.2% of cases. We know that this value represents 58 cases, so we can use a rule of three in order to determine the prior value. This is seen bellow:

100% -> x

110.2% -> 58

110.2*x = 100*58

x = 5800/110.2 = 52.63

Which is approximately 53 cases.