 
 <translate> Give the step-by-step reasoning process and then the final answer. On the last night that roller skate rink was open, 40 people showed up to roller skate one last time. When all 40 people skated at one time, how many wheels were on the floor? <hau> Bayyana tsarin tunani mataki-mataki sannan kuma amsar karshe. A daren karshe da aka bude filin wasan, mutane 40 sun zo su yi wasan kwallo a karo na karshe. Lokacin da mutane 40 suka yi tsere a lokaci ɗaya, ƙafafun nawa ne suke a ƙasa? 