"She eats three times."

Translation: Dia makan tiga kali.

[Lims41]

why is memakan incorrect?

[Rick392366]

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 ☺.

[TonyBerjaya]

She must be straving