Answer:
512
Step-by-step explanation:
Let the number of 7th graders in the school is x.
As three-quarters of them play at least one sport, so, the number of 7th graders who play sport =
.
Among the 7th graders who play sports, half of them play more than one sport. So, the number of 7th graders who play more than one sport
.
Among the 7th graders who play more than one sport, one-third of them play more than two sports. So, the number of 7th graders who play more than two sport
.
Among the 7th graders who play more than two sports, one-quarter of them play more than three sports.
So, the number of 7th graders who play more than three sport
.
7th graders play more than three sports at the school= 16



Hence, the total numbers of 7th graders in the school are 512.