The distance between you and train 1 at time t is
20.6 km + (0.2 km/h) t
and the distance between you and train 2 at time t is
59.7 km - (2.1 km/h) t
The trains are an equal distance away from you when
20.6 km + (0.2 km/h) t = 59.7 km - (2.1 km/h) t
Solve for t :
(2.3 km/h) t = 39.1 km
t = 17 h
at which point they are
20.6 km + (0.2 km/h) (17 h) = 24 km
away from you.