Given the following reasoning and answer, what was the question? Mark played for a total of 20 + 35 = 55 minutes. So, he was on the sideline for 90 - 55 = 35 minutes.
 The answer: 35
The question In a 90-minute soccer game, Mark played 20 minutes, then rested after. He then played for another 35 minutes. How long was he on the sideline?