A car starts at zero and gets to 50 km/hour in 10 minutes. What is the initial velocity?

The initial velocity is the speed and direction of the car at the beginning

of the event.

You just said that the car "starts at zero". You might mean that it starts at

"location zero". But then you go on to tell us its speed after 10 minutes,

so it sounds like the "zero" at which it starts is zero speed.

In that case, its initial velocity is zero.