This is terrible. It's bad enough to make users to type garbage during registration, but on every post? WTF? Use better antispam protection that doesn't create user friction. Google about it. don't just do garbage like Write " viserion069 " backwards or 5 x 25 + 3 = ?
That's just terrible. Please remove the lame captcha and question. Use Google's Recaptcha. Honestly. Feels like teenager's work.