STRIKING the right balance between the formal and informal in the school curriculum is the key to a child's healthy development, says the Director of Education, Dominic Wong Shing-wah. Mr Wong was addressing the gathering at Liu Po Shan Memorial College's speech day held last week. The director said students who had a positive outlook and well-formed personalities were equipped to put their academic knowledge and skills to use in the outside world. Personality was an important factor in adult life, Mr Wong stressed. Working well with others and serving the community properly depended to a large extent on how one's personality had developed during the school years, he told the students. ''In recent years, Hong Kong has been developing and advancing at a very great speed, and young people have to face tremendous challenges of all kinds.'' To be able to face such challenges, students should develop their potential, gain knowledge and skills, learn to think for themselves and be aware of what was happening around them, Mr Wong said. ''It is only then that young people will be able to live a meaningful life.'' Mr Wong congratulated the graduates, and wished them every success in their future. Also speaking at the ceremony was school supervisor Liu Lit-man, who quoted the ancient Chinese saying that it takes 100 years to educate people but only 10 years to grow a tree. Mr Liu said the adage underlined the importance of a slow but steady education process that built a sturdy foundation for a prosperous society. School principal Wong Shiu-gun presented the school report, announcing that Liu Po Shan Memorial College now had 30 classes, from Forms One to Seven, with 1,110 students enrolled for the 1992-93 academic year. He said 47 of the 56 Form Seven students who took the Advanced-level Examination last year passed, and the average pass rate for each subject was 87.07 per cent. The students picked up 62 distinctions and credits. At last year's HKCEE, 111 of the 156 Form Five students received five passes or above. The pass rate was 71.15 per cent, and a total of 202 distinctions and credits was received. The speech day ended with a variety concert put up by students. The programme included an Italian folk dance by the dance students and a Cantonese song performed by the school choir.