Final answer:
There are 3,150 families with school-aged children living at home in the city, calculated by taking 7/10 of the total 4,500 families.
Step-by-step explanation:
If 7 out of every 10 families in a certain city have school-aged children living at home, and there are 4,500 families in the city, we can calculate the number of families with school-aged children by finding 7/10 of 4,500.
First, we divide 4,500 by 10 to find out what 1/10 of the families would be:
4,500 / 10 = 450
Now, we multiply this figure by 7 to find out what 7/10 of the families would be:
450 * 7 = 3,150
Therefore, there are 3,150 families with school-aged children living at home in the city. The correct answer is D) 3,150.