State high-school teachers have voted to boycott university entrance exams, endangering the chances of thousands of students who have applied to enter universities in Greece and abroad. The Federation of Higher Education Personnel, which represents nearly 60,000 high-school teachers nationwide, overwhelmingly voted Thursday to continue a strike over pay and conditions. ``We will stage 24-hour strikes whenever the government reschedules the exams,'' said one union official, who refused to be identified. The exams conducted by the state high-school teachers were originally set for June 14. The teachers want $107 more a month in pay and a reduction in the number of hours they must teach each week. High-school teachers receive a starting salary of about $476 a month, which can rise to $833 a month. They must teach 21 hours each week and want that cut to 18 hours a week.