South Korean mothers knelt in prayer, the stock market opened late and the military grounded flights to help teenagers taking a college entrance exam on Thursday that could shape the course of their lives.

Some 585,000 students took the state-sponsored College Scholastic Aptitude Test. The exam determines the university they will attend, but getting into an elite college often means being at the top of the list for the best jobs after graduation and being considered one of the most eligible people to marry.

Education-obsessed South Korean parents spend huge sums of money on the best tutors, cram schools, private schools and even nutritionists who will fashion a diet suited for studying to give their child an advantage.

Most teenagers preparing for the test usually spend about 14 to 16 hours a day in studies.

Mothers by the tens of thousands prayed for good results at Christian churches as well as Buddhist temples known for having links to education as well as .

Many companies and financial markets in Asia's fourth largest economy opened about an hour later than usual to keep cars off the road so test-takers would not get caught in morning traffic.

The Defence Ministry grounded military flights during test time to cut down on noise so students could better concentrate.

Police patrol cars, motorcycles and fire trucks were on standby to transport possibly tardy students.

Once students arrived at the test site, many had to undergo searches with metal detectors to make sure they were not carrying mobile phones and other gadgets, which are banned now but have been used by many test-takers in the past to cheat.

For many in South Korea, test day is symbolic of an education system that has gotten out of control.

Social commentators say the reason South Korea has the lowest birth rate in the developed world is because of the high cost and high pressure of the education system.