Exercise 4
A grow from 13.1 millions to 14.4 millions means to grow

millions. So, the question is: which percentage of 13.1 is 1.3? Well, we have to find a number x such that

Solving for x, you have

Exercise 5
27% is a bit more than 25%, which is a quarter. So, we expect to find a pie chart with one slice occupying roughly one quarter of the pie. The example that best suits this requirement is B (A is almost half, and C is less than one quarter).