Solve the given equations and answer the following question

I. 9x² - (116x/a) + 25 = (2x²  - 4x/a + 4)

II.(10y² - (600y/b) + 200) = (5y² - (150y/b) + 100)

III. z² - (a + b)z + 10a = 0

Note:

i) Smaller root of equation I is P and higher root of equation II is Q

ii) a is 6 less than b and one of the root in equation III is 4

If the speed of vehicle A is 12Q and the speed of vehicle B is 30P.Difference between the time to travel S km is 5 hours.If the speed of vehicle B is increased by 50%. Find the time taken to travel the same distance.