A police van moving on a highway with a speed of `30 km h^(-1)` Fires a bullet at a thief's car speeding away in a same direction with a speed of `192 km h^(-1)`. If the muzzle speed of the buller is `150 m s^(-1)`, with what speed does the bullet hit thief's car? .
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Explanation

Let `v_(b)` is velocity of bullet `v_(p)` is velocity of police van and `v_(t)` is velocity of thief's car. Then, speed of the bullet with respect to the thief's car
`v_(bp)=v_(b)-v_(p)`
`v_(b)=v_(bp)+v_(p)=150xx(18)/(5)kmh^(-1)+30kmh^(-1)=570 kmh^(-1)`
`v_(bt)=v_(b)-v_(t)=570 kmh^(-1)-190 kmh^(-1)=380 kmh^(-1)`