if he bought the bike for $400 and lost 35% of his profit, you would divide 35 by 100. Next, you would multiply that number (0.35) by 400. When you do that, you get an answer of $140. In conclusion, if he bought the bike for $400 and sold it at a loss of 35%, he would lose $140 from that $400.
Additionally, if you wanted to know what exactly he sold it for, you would simply subtract 140 from 400. Which would be $260.
So, he bought the bike for $400, but when he resold it, he lost $140 of that pay. Basically, he resold the bike for $260.
I hope this helps! :) Let me know if you need help with anything else!