A tram moves along a straight track at a constant velocity of 12 m/s.
It then slows down uniformly from 12 m/s to 4.0 m/s in 5.0 s.
The tram travels a total distance of 160 m during this journey.
For how long did the tram move at constant velocity?
8.3 s8.3\ \mathrm{s}8.3 s
13 s13\ \mathrm{s}13 s
10 s10\ \mathrm{s}10 s
15 s15\ \mathrm{s}15 s