Answer
37 min 20 s
Work Step by Step
Since it takes Candy 70 mins to deliver all the papers, she delivers $\frac{1}{70}$ of the papers in 1 min.
Since it takes Tim 80 mins to deliver all the papers, he delivers $\frac{1}{80}$ of the papers in 1 min.
Working together, they can deliver $\frac{1}{70} + \frac{1}{80} = \frac{3}{112}$ of the papers in 1 minute. Therefore, it takes them $\frac{112}{3} = 37.3$ minutes to deliver the papers, or 37 minutes and 20 seconds.
