Person 1 can do a certain job in twenty-one minutes, and person 2 can do the same job in twenty-eight minutes. when completing the job together, which expression would be used to represent the amount of work done by person 1?
21
1/21
x/21
21x

would be used to represent the amount of work done by person 1.

Step-by-step explanation:

When someone does a work in x time,

Then, the work done by the person in one day =

Given,

Time taken by person 1 = 21 minutes

Thus, by the above statement,

The one day work of person 1 =

Hence, would be used to represent the amount of work done by person 1.

Second option is correct.

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