Question 1 is unclear to me, so I assume you want to say that the planes leave from same airport and you want to find the time when they are 450 kms apart.
Let t be the time required for these two plane be 450 kms apart.
So distance (x) travelled by plane A in t hours = 960t (since distance = speed * time)
and distance (y) travelled by plane B in t hours = 810t
Given, plane A is 450 kms ahead of plane B in t hours.
So, x = y + 450
=> 960t =810t +450
=> 960t - 810t = 450
=> 150t = 450
=> t =450/150 = 3 hours
So it will take 3 hours for plane A to get 450 kms ahead.
Distance travelled by bus A be x in t time.
Distance travelled by bus B be y in t time.
x = 80t
y = 108t
Given, they are moving in opposite direction so sum of the distance should be equal to 329km at time t.
x + y =329
=> 80t + 108t = 329
=> 188t = 329
=> t =1.75 hours
or t = 1 hour 45 minutes
or t = 105 minutes