"She eats three times."
Translation:Dia makan tiga kali.
why is memakan incorrect?
It's not incorrect (it's adjusted now).
It's just that it's rarely said like that, 'me-' is usually dropped with verbs like 'makan', 'minum', 'mohon'.
Side note : In colloquial/daily conversation, 'me-' is usually dropped with other verbs as well ☺.