Question

Frederica is sitting on a moving train. She watches the telephone poles fly past. She knows that the poles in this area are 1/4 mile apart. Every minute, 3 poles pass her. In the reference frame of the poles, how fast is the train moving?

Answer 1

If every minute 3 poles past and poles are 1/4 mile (0.25 mile) apart;

3x0.25 = 0.75
Train moves 0.75 mile/per minute


If you want the train's speed per hour, then;
x = 60x0.75
x= 45miles per hour is the speed of the train