If the bullet goes 500 m each second, it means it travels:

60 × 500 = 30,000 m in one minute

60 × 30,000 = 1,800,000 m in one hour

`(1, 800, 000 text(m/h))/(1,000) = 1 800text( km/h)`

So the bullet is travelling 1,800 km/h.