Deceleration of a particle

1. The problem statement, all variables and given/known data
"A car is approaching traffic lights. The car is travelling with speed 10ms-1. The driver applies the brakes to the car and the car comes to rest with constant deceleration in 16s. Modelling the car as a particle, find the deceleration of the car."

2. Relevant equations
v = u + at

3. The attempt at a solution
s =, u = 10ms-1, v = 0ms-1, a = ?, t = 16s

v = u + at
0 = 10 + 16a
a = -10 ÷ 16
a = -0.625ms-2

The answer given is 0.625ms-2. Why is the answer positive and not negative?

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