Well, we know that 50% of people left. Since there can be no greater than 100%, we know that [tex]100% - 50% = 50%[/tex] stayed.
Now, we need to figure out what 50% of 210 is. To do this, we can convert 50% into a fraction:
[tex]50% = \dfrac{50}{100} = \dfrac{1}{2}[/tex]
Now, let's multiply this fraction by 210 to find a number of people. This would be:
[tex]210 \,\textrm{people} \cdot \dfrac{1}{2} = 105 \,\textrm{people}[/tex]
Our answer is 105 people.
