题干

甲乙两个学生原计划每天自学的时间相同,若甲每天自学时间增加40分钟,乙每于自学时间减少40分钟,则乙5天的自学时间仅等于甲1天的自学时间,求甲乙原订每天自学时间是多少?(用算术、方程两种方法解答)

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答案(点此获取答案解析)

解:(1)算术法:

(40+40)÷(5﹣1)+40,

=80÷4+40,

=20+40,

=60(分钟),

(2)设甲乙原计划每天自学的时间相同是x分钟,则变化后的甲每天自学时间为x+40分钟,乙自学时间是x﹣40分钟,根据题意可得方程:

5(x﹣40)=x+40,

5x﹣200=x+40,

4x=240,

x=60,

答:甲乙原订每天自学时间是60分钟.

同类题5

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A

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