v^2-u^2/2s = a

given s = 500, u= 18km/hr and v = 54km/hr

Now substituting for s,u and v and a we get

54^2 - 18^2/2 x 500 = a

a = 18 x 18/125

Next let u = 54km/hr and v = 72km/hr and a = 18 x 18/125

v^2 - u^2/2a = s

Now substituting the values for u, v, and a we get

72^2 - 54^2 x 125/2 x 18 x 18 = s

7 x 125/2 = 437.5km

So it will travel a distance of 437.5km further.