Lutheran South Academy is a private pre-kindergarten through 12th grade Lutheran school located in Houston, Texas, United States. The school is a member of the Houston Area Independent Schools, a group of roughly 50 private, parochial and independent institutions in the Greater Houston area.
There are roughly 10 private schools in the Houston Area Independent Schools.
It's neither correct nor incorrect because we only know there are roughly 50 schools in total among the three types, but we don't know exactly how many there are for each type of school listed. It's difficult because the system probably just saw the "50" in the text and knew that it was not equal to 10, but it was not able to understand the complex logic in the question/text.