Work Step by Step
First, we find how many copies copier A made in the initial time: copies $ = 40(6) = 240$ This means that there are 520-240=280 copies left to be made. Thus: $280 = 40t + 30t \\ t = 4$
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.