 <translate> 40 people were roller skating and they all had 2 feet which means there were 40 * 2 = 80 feet. Each foot needs a roller skate and each roller skate has 4 wheels so 80 * 4 = 320 wheels when everyone skated.
The final answer: 320. <yor> 40 eniyan ni wọn n fi kẹkẹ rin, gbogbo wọn si ni ẹsẹ meji eyi to tumọ si pe 40 * 2 = 80 ẹsẹ. Ẹsẹ kọ̀ọ̀kan nílò ọkọ̀ ayọ́kẹ́lẹ́, ọkọ̀ ayọ́kẹ́lẹ́ kọ̀ọ̀kan sì ní kẹ̀kẹ́ mẹ́rin, nítorí náà 80 * 4 = 320 kẹ̀kẹ́ nígbà tí gbogbo èèyàn bá ń sáré. Ìdáhùn tí wọ́n fún un níkẹyìn ni pé: 320. 