UC知道初2英语和数学,在线等答案哦,要过程!
来源：百度知道 编辑：UC知道 时间：2024/05/07 09:21:13
某次数学竞赛共有20道选择题,答对一题记5分,答错一题扣2分,不答记0分.某同学共得48分,那么他最多答对了几题?
英语:A man from the UK remembered the correct order of 1820 playing cards,after seeing them just once.(用从句转换)
_________________________________________________________.
英语:A man from the UK remembered the correct order of 1820 playing cards,after seeing them just once.(用从句转换)
_________________________________________________________.
设做对X道,错Y道
5X-2Y=48 (1)
X+Y≤20 (2)
由(1)得,Y=(5X-48)/2 (3)
把(3)带入(2)得
7X≤88
X≤88/7≈12.5
所以,最多做对了12题.
_______________________
A man from the UK remembered the correct order of 1820 playing cards,after seeing them just once.(用从句转换)
A man from the UK remembered the correct order of 1820 playing cards after he saw them just once.