I am honestly not sure, because the author is using some serious fuzzy math, but I don't think that's what the article is saying. 100 dud 25k investments means

I am honestly not sure, because the author is using some serious fuzzy math, but I don't think that's what the article is saying. 100 dud 25k investments means a loss of $2.5 million. I think it is saying that if one company you invest in sells for $25million and you have a 10% stake you have covered your $2.5 million loss on 100 bad investments. That's clearly missing the point that a 25k investment is pretty much never going to grant you 10% of a startup these days... When you factor in dilution/etc... the risk/reward ratio gets a little less obvious.