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?

a. 21

b. 1/21

c. x/21

d. 21x

Question

Mathematics

Justine Edwards

24 December, 05:53

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?

a. 21

b. 1/21

c. x/21

d. 21x

+5

Answers (2)

Know the Answer?

Yosef Clements · Answer 1

When completing the job together, the expression that would be used to represent the amount of work done by one person is 1/21. The correct answer is B.

1/21 + 1/28 = 1 if done together.

Tara Lynch · Answer 2

The correct answer is:

C) x/21

Explanation:

Since Person 1 can complete the entire job (100% = 1/1 = 1) in 21 minutes, this person can complete 1/21 of the job per minute. This is Person 1's rate. If x is the amount of time it takes both people together to finish the job, then the amount of work Person 1 does would be (1/21) (x) = x/21.

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?a. 21b. 1/21c. x/21d. 21x

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?

a. 21

b. 1/21

c. x/21

d. 21x