作业帮 > 英语 > 作业

Fred's final mark in an online course was determined entirel

来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:英语作业 时间:2024/05/15 20:19:40
Fred's final mark in an online course was determined entirely by two exams.The mid-term exam was out of x marks and was worth 25% fo his final mark.The final exam was out of 2x marks and was worth 75% of his final mark.Fred scored 40 marks on the first exam and 60 marks on the second exam.Determine the value of x if Fred earned a final mark of 50% in the course.
Fred's final mark in an online course was determined entirel
由题,可列方程
(40/x) ×0.25 + [60/(2x)]×0.75 =0.5
即,(10/x) + (22.5/x) =0.5
32.5/x =0.5
解得,x=32.5/0.5=65
so,the value of x is 65