Question 1022569
Call the time he took on the first part, t.
Then the time he took on the second part was 3.5-t.
Then we can write, noting that rate times time = distance,
63t + 54(3.5 - t) = 198
63t + 189 - 54t = 198
9t + 189 = 198
9t = 9
t = 1 hour at 63 mph
and then
3.5-t = 2.5 hours at 54 mph