.英文的,用加减乘除的方式帮我~
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.英文的,用加减乘除的方式帮我~
1.There are three bulbs in a shop.One lights up every 4 mintues,another bulb lights up every 8 mintues and the third bulb lights up every 11 mintues.
All the bulbs light up together when Ali walked into the shop.
How many times will see at least 2 bulbs light up together if he was in the shop for 3/4 hour
如题,哪位英语好的请用【加减乘除】的方式帮我..
1.There are three bulbs in a shop.One lights up every 4 mintues,another bulb lights up every 8 mintues and the third bulb lights up every 11 mintues.
All the bulbs light up together when Ali walked into the shop.
How many times will see at least 2 bulbs light up together if he was in the shop for 3/4 hour
如题,哪位英语好的请用【加减乘除】的方式帮我..
![.英文的,用加减乘除的方式帮我~](/uploads/image/z/17043290-26-0.jpg?t=.%E8%8B%B1%E6%96%87%E7%9A%84%2C%E7%94%A8%E5%8A%A0%E5%87%8F%E4%B9%98%E9%99%A4%E7%9A%84%E6%96%B9%E5%BC%8F%E5%B8%AE%E6%88%91%7E)
时间共有3/4 hour即45min,
三灯同时亮的周期8*11=88>45,所以45min内三灯不会再同时亮,
L1和L3同时亮的周期是4*11=4445,所以L2、L3在45min内也不会再同时亮,
而因为4、8的最小公倍数是8,所以L1、L2同时亮的周期是8min,
而45=8*5+5,所以L1和L2同时亮有5次,
综上所得,所求为1+8=9.
(不算他刚进去那次)
三灯同时亮的周期8*11=88>45,所以45min内三灯不会再同时亮,
L1和L3同时亮的周期是4*11=4445,所以L2、L3在45min内也不会再同时亮,
而因为4、8的最小公倍数是8,所以L1、L2同时亮的周期是8min,
而45=8*5+5,所以L1和L2同时亮有5次,
综上所得,所求为1+8=9.
(不算他刚进去那次)