see, first satisfy the first condition --between two specified cars there should be
exactly 4 cars so posiible ways can be ->1) # __ __ __ __ #__ __(# denote the specified cars)
2)__@ __ __ __ __ @__
3)__ __ % __ __ __ __ %
so , we have 3 ways for selection of parking slots for two cars now these two cars can also arrange in 2 ways __@ __ __ __ __ @__ =3.2!
now we are left with 6 positions and 6 cars can be parked in 6! ways
now, all 8 have to be parked so it is going to be 6.6!(answer)