I'd be surprised if it takes more than 5 seconds for a human to solve each. Keep in mind that 27 seconds was the time in the queue from submit to solve. 24 seco

I'd be surprised if it takes more than 5 seconds for a human to solve each. Keep in mind that 27 seconds was the time in the queue from submit to solve. 24 seconds of that might have been spent in the backlog and 3 seconds being viewed and solved by a human. Additionally, it supposes that all images being solved are the kind that a human must do. Tons of CAPTCHA images being output by naive generators can be solved automatically. I'd be surprised if every image submitted isn't going through an automated solver first with only the < 95% confidence ones being sent to a human. Actually, you could do a hybrid model where every image is auto-solved and a human can either click to confirm that the auto-solver got it right or manually type a new response. That should get your time per solve down to a second or two each.