Stardust the unicorn, covered a distance of 50 miles on his first trip to the forest. on a later trip he travelled 300 miles while going three times as fast. his new time compared with the old time was:

For this case, the first thing we must take into account is the following definition:
 d = v * t
 Where,
 d: distance
 v: speed
 t: time
 Substituting values we have:
 Trip 1:
 50 = v * t1
 We cleared t1:
 t2 = (50) * (1 / v)
 Trip 2:
 300 = (3 * v) * t2
 We cleared t2:
 t2 = (300/3) * (1 / v)
 t2 = (100) * (1 / v)
 Rewriting:
 t2 = 2 (50) * (1 / v)
 t2 = 2 * t1
 
 His new time compared with the old time was:
 Twice the old time.
 t2 = 2 * t1.