Following the previous scenario: there is a special clock that counts seconds instead of hours, minutes, and seconds. The clock started counting from 0 and after some time the clock showed 5259 seconds. When Roberta looked at the clock, it showed 4407 seconds. 

As a continuation, suppose that after Roberta's check, she spent 4087 additional seconds completing a task. Combining the time she spent on the task and the time that had passed since she checked, how many seconds total had passed since she first checked the clock?