神马作文网.英文的,用加减乘除的方式帮我~
来源：学生作业帮 编辑：神马作文网作业帮 分类：英语作业 时间：2024/11/18 20:51:46
.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..
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）