40k deposited, 10:1 leverage, 400k capital used.
Profit of 90k = 22.5% return...
A profit of 90K, on 40K deposited, is a 225% return on the money you needed to make that profit. The fact that the broker leveraged you makes no difference, because you do not owe the broker anything at the end. They fronted you what was required for you to make the profits.
But it is still the same. You invested 40K, made 90K. If he was not leveraged, he would have needed 400K to make 900K. It is still 225% profit.