1. The problem statement, all variables and given/known data A student riding a bicycle begins to go downhill and accelerates at a rate of 1.8m/s2. If the acceleration lasts for 2.4s, and the final speed of the bicycle is 10.2m/s, at what speed was he initially travelling? a = 1.8 t = 2.4 vf = 10.2 vi = ? 2. Relevant equations a = vf - vi / t 3. The attempt at a solution I first isolated vi to solve for the problem and got : vi = vf-a/t and then plugged in the variables but it didn't work.