Calculating the percentage increase

Question

A doctor was seeing 3 patients a day.

He then started to see 18 people a day.

What is the percentage increase? And how do I work this out?

Answer 1

Notice, the percentage increase is calculated on the basis of initial value, in this case percentage increase is $$=\frac{\text{(final number of people)}-\text{(initial number of people)}}{\text{(initial number of people)}}\times 100$$$$= \frac{18-3}{3}\times 100=\frac{15}{3}\times 100 =500\ \text{%}$$