To get simplest form you make it the smallest fraction you can make it by dividing both sides by the same number until it's not possible anymore Hope that helped!
I belive it is slower because the scooter was 30 feet per 2 seconds. 30+30+60 feet, 2+2= 4 seconds= 60 feet and 4 seconds which makes the 55 feet per 4 seconds slower.