Chan scored the highest mark in chemistry, while Young did the same in Mandarin.

Chan, who took the exam in June when she was 15, said she worked hard on chemistry out of intense interest in the subject, although she was intrigued by other subjects as well, such as languages and mathematics.

She already has 10 A* - the best grade - and a B under her belt in other exams.

She came out top in Hong Kong in geography and foreign language Spanish. A native English, Mandarin and Cantonese speaker, she also took French classes at school, and notched up an A* in foreign language French and a B in mother language French, which she took to challenge herself.

'I work hard, but I also make sure I keep a healthy balance of life,' she said.

Outside the classroom, she says she does not spend all her time glued to social networking websites. She has played on the school's netball and tennis teams and does athletics training. She came 12th out of 2,000 runners in her category in the 10 kilometres at the Standard Chartered Marathon last week.

She has not yet decided whether to study law or chemistry at university. However, she said she was not under any pressure to choose from her family. 'They let me do what I enjoy most. They're not like tiger mums, and that's very important to me,' she said.

Tung Chit-cheung, also from the French International School, scored the highest mark in the Latin exam in Hong Kong.

Mary Lawton, who heads the school's international section, said: 'I'm very proud of my students. I thank the parents and teachers for delivering the A-team and providing one of the best educations in town.'