Final answer:
The number of houses Habitat for Humanity can build varies directly with the number of volunteers.
Step-by-step explanation:
The relationship between the number of houses Habitat for Humanity can build and the number of volunteers is a direct variation. This means that as the number of volunteers increases, the number of houses that can be built also increases, and vice versa.
To find out how many houses can be built with 60 volunteers, you need to know the constant of variation, which represents the number of houses that can be built with one volunteer. Once you have that information, you can simply multiply the constant by the number of volunteers.
For example, if the constant of variation is 2 houses per volunteer, then with 60 volunteers, you can build 60 × 2 = 120 houses.