We have the next information
v=speed =85km/hr
t=30 sec
First we need to convert 85km/hr to m/s

the equivalence to convert km/hr to m/s is
1 m/s =3.6 km/hr

then we will use the next formula in order to know the distance

where v is the speed , d is the distance and t is time
In order to find the distance we need to isolate d of the formula above

in our case
v=23.611 m/s
t=30 sec
we substitute the values

The answer is 708.33 m