You don't have to use any equation or formula for this question. We will just use our imagination :)

(This solution is similar to my post here)
First, imagine the scene as you're on the ground, standing, looking at the runners. You see that they're 35 m away and running at the same direction at 1.85 m/s and 1.65 m/s.

Now, imagine the scene as you are Runner #2. You're 35 m behind Runner #1. You both start running. Ignore the grounds. What do you see? You see that Runner #1 gets closer at 0.2 m/s!

(it's 1.85 - 1.65). We just calculated the relative speeds. And now, he's 35 m ahead and coming closer at 0.2 m/s. When would you meet? It's so easy,

$\displaystyle V = \frac{x}{t}$

$\displaystyle 0.15 = \frac{35}{t}$

$\displaystyle t = \frac{35}{0.2}$

$\displaystyle t = \frac{350}{2} = 175$ seconds

Now you work the rest :)