Can you help to find the acceleration of the traveling car?

Question

A car traveling at 15m/s starts to decelerate steadily. It comes to a complete stop in 10 seconds. What is its acceleration?

Answer 1

a = (v_f - v_i) / t = [(0 m/s) - (15 m/s)] / (10 s) = -15/10 m/s² = -1.5 m/s²