Solution
For this case we can set up the following formula
D= d1 +d2
d= 45x +(9-x)*60 = 480
And solving for x we got:
45x +540 -60x =480
540-480 = (60-45)x
60 = 15 x
With x representing the time travlling at 45 km /hr
x= 4
And then the time travelling at 60 km /hr is 9-4= 5hr
Then the final answer is:
X= 60 km/hr * 5 hr= 300 km