 
<translate> Don amsa wannan tambayar, ya kamata mu san cewa: Makarantun sakandare a Koriya ta Kudu suna koyar da ɗalibai na shekara uku, daga aji na farko (shekaru 15 zuwa 17) zuwa aji na uku (shekaru 17 zuwa 19), kuma ɗalibai sukan sauke karatu sa'ad da suke da shekara 18 ko 19. Amsar ita ce: shekaru 15 zuwa 17. <eng> To answer this question, we should know that: High schools in South Korea teach students for three years, from first grade (age 15 -- 17) to third grade (age 17 -- 19), and students commonly graduate at age 18 or 19.
The answer: age 15 -- 17. 