Originally, Zhang and Zhao were 750 meters apart. Zhang walked 60 meters per minute, and Zhao walked 90 meters per minute. After they started facing each other, press 1, 3, 5, 7, ... (continuously odd minutes) to turn around and walk in the opposite direction. How many minutes can Zhang and Zhao meet each other after they set off?
张、赵两人原来相距750米，张每分钟走60米，赵每分钟走90米，两人相向出发后按1、3、5、7、…(连续奇数分钟)调头反向行走，求张、赵两人出发后几分钟可以相遇？
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