If your high school granted admissions on the basis of a single test what would the demographics look like? Well, NYC does this and the results are quite amazing. See the numbers here...

I did not know NYC did this for admission to various high schools. Quite extraordinary.

Here are the results of admitting students to select high schools in New York City based SOLELY on a competitive exam to get in (HT: Newmarksdoor).

—Stuyvesant offered admission to 9 black students; 24 Latino students; 177 white students; and 620 students who identify as Asian. 

—Bronx Science offered admission to 25 black students; 54 Latino students; 239 white students; 489 Asian students; and 3 American Indian/Alaskan Native students. 

—Brooklyn Tech offered admission to 110 black students; 134 Latino students; 451 white students; 960 Asian students; and 5 American Indian/Alaskan Native students.

Read more here:  Most Eighth Graders Matched to a High School of Their Choice

Read more on the use of a single test to determine admissions:  Debate of Single-Test Admissions Policy Divides on Access and Race