Bǎifēnzhī shíwǔ de xuéshēng méiyǒu tōngguò kǎoshì.
Fifteen percent of students failed the exam.
Tips
grammar
Chinese percentages are written 百分之 N (bǎifēnzhī N — literally 'of one hundred parts, N'), with the percentage following 之. So 50% = 百分之五十 (bǎifēnzhī wǔshí). The order is the reverse of English '15 percent'.