老张和老王两个人在周长为400米的圆形池塘边散步。老张每分钟走9米,老王每分钟走16米。现在两个人从同一点反方向行走,那么出发后多少分钟他们第二次相遇?( )
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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