The population of New York City is about 18.8 million people. This is about 9.9 million more people than the population of Chicago. Write and solve an equation to find the approximate population of Chicago.

9/1 million

28.7 million

9.9 million

8.9 million

Let the population of Chicago be x.

Now we are given that the population of New York City is 9.9 million more than the population of Chicago.

Therefore, we can write the equation:
18.8 = x + 9.9

Solving for x:
x = 18.8 - 9.9
x = 8.9

So the approximate population of Chicago is 8.9 million.