More than 85 percent of the 2013 senior class participated in Prince George’s County’s “SAT School Day” last week, a chance for students to take the college entrance exam for free during school hours.

“We are extremely excited that so many of our students participated in the 2012 SAT School Day,” Alvin L. Crawley, the interim school superintendent, said in a statement. “We will continue to make investments in innovative initiatives and programs that prepare our students for the increasing demands of college and the workplace.”

The college entrance exam, which is normally taken on Saturdays, was scheduled for Oct. 17 during school time to make it more convenient for students. It was offered at no cost to help those who couldn’t afford the test so that more students would take it..

The strategy appeared to pay off. More than 6,800 students registered for the exam last week. Last year about 5,200 sat for the SAT; four years ago about 5,000 took the test.

High school juniors will take the SAT during a second “SAT School Day” in the spring.