Speed of the police jeep = 54km/h=15m/s
Muzzle speed of the revolver hit by the police=100m/s
Total velocity of the bullet= Speed of the car + muzzle speed= 100m/s + 15m/s= 115m/s
Velocity of the thief’s car= 126km/h= 126x 5/18= 35m/s
Relative velocity of the bullet with respect to thief=Total velocity of the bullet – Velocity of the thief’s car= 115m/s – 35m/s= 80m/s
So bullet will hit the car of the thief at a velocity 80 m/s