Calculating Acceleration of a Bike Rider

Scenario:

A child rides her bike at a rate of 12.0 km/hr down the street. A squirrel suddenly runs in front of her so she applies the brakes and slows to 8.0 km/hr in 0.25 sec.

Calculation:

Using the formula v = u - at:

8 = 12 - a x 0.25

a = 4/0.25 km/hr/sec

a = 16 km/hr/sec

Conclusion:

The acceleration of the bike rider during this period is 16 kilometers per second.

What is the acceleration of the bike rider during the period when she applies the brakes?

It should be 16 kilometers per second.