Answer:
200 minutes ; 3 hours and 20 minutes.
Explanation:
If you write a proportion in the form
miles/minutes = miles/minutes
you would get 3/50 = 12/x
from there you cross multiply to get
3x=600, and solve that to get 200 minutes.
another way was to see that 12 is 3*4, and multiply 50 by 4 to get the same answer.