Question

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?

Answer 1

I hope this helps you



1/21+1/28=1/t


4/84+3/84=1/t


5/84=1/t


t=84/5


84/5 1



21 ?



?.84/5=1.21



?=5/4