if I leave home to go to the beach and at 7:05 am I am 1/3 of the way there. At 7:25am I am 3/4 of the way there. What time will I arrive at the beach.
time between 7:05 and 7:25 = 20 min
fraction of the distance covered = 3/4 - 1/3 = 5/12
So, 20/(5/12) = 48 min to cover the whole distance.
Time to cover the remaining 1/4: 12 min.
ETA: 7:25 + 0:12 = 7:37