156025

I knew that there were 52 total legs. I knew that Zios had 3 legs each and Zepts had 7 legs each. I guessed and checked several different amounts of Zios. That gave me different numbers of legs that when I divided by 7 didn't give me whole numbers of Zepts. Then, I tried 8 Zios which gave me 24 legs. That means that all of the Zepts had 28 legs which is a multiple of 7...There were 4 Zepts!