Stopping distances maths A2

The brakes of a train can produce a retardation of 1.7ms-2. If the train is travelling at 100km h-1 and applies the brakes what distance does it travel before stopping? (have done this part and got the correct answer of 227m).

I am stuck on the part below.

If the driver applies the brakes 15m too late to stop at the station then what speed is the train travelling when it passes through that station?