Each of 10 machines works at the same constant rate doing a certain job

题目

Each of 10 machines works at the same constant rate doing a certain job. The amount of time needed by the 10 machines, working together, to complete the job is 16 hours. How many hours would be needed if only 8 machines, working together, were used to complete the job?

选项

解析

工作问题中的时间、效率和工作量，与行程问题中的时间、速度（效率）和路程，是同一类数量关系： - 行程问题：时间×速度=路程 - 工作问题：时间×效率=工作量已知：\( 16 × 10x = \text{工作量} \)。问题：若\( t × 8x = \text{工作量} \)（同一工作量），求\( t = ? \) 求解\( t \)： \[ 16 × 10x = t × 8x \] \[ t = 20 \] 答案：B

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