Some thirty poems in the book
Are poor, you say. Egad!
If you’ve found thirty good ones, too,
The book is great, not bad.

[‘Triginta toto mala sunt epigrammata libro.’
Si totidem bona sunt, Lause, bonus liber est.]

Martial (AD c.39-c.103) Spanish Roman poet, satirist, epigrammatist [Marcus Valerius Martialis]

Epigrams [Epigrammata], Book 7, epigram 81 (7.81) (AD 92) [tr. Marcellino (1968)]
    (Source)

"To Lausus." (Source (Latin)). Alternate translations:

Thou thirty epigrams dost note for bad:
Call my book good if thirty good it had.
[tr. Killigrew (1695)]

For thirty bad epigrams here you may look:
If as many good ones, it is a good book.
[tr. Elphinston (1782), Book 12, ep. 7]

In this whole book there are thirty bad epigrams; if there as many good ones, Lausus, the book is good.
[tr. Bohn's Classical (1859)]

"Take all your book, and there are thirty bad epigrams in it." If as many are good, Lausus, the book is a good one.
[tr. Ker (1919)]

You’ve read my poems and condemn
Some thirty, so you say, of them:
The book’s a good one I submit,
If there are thirty good in it.
[tr. Pott & Wright (1921), "Proportions"]

"There are thirty bad epigrams
in your book, at least."
If there are that many good ones,
Lausus, I'll be pleased.
[tr. Bovie (1970), mislabeled 7.18]

"There are thirty bad epigrams in the whole book." If there as many good ones, Lausus, it's a good book.
[tr. Shackleton Bailey (1993)]

"Your book as thirty epigrams unneeded."
I've only thirty clunkers? I've succeeded.
[tr. Wills (2007)]

"In this book, thirty poems are bad," you state.
Lausus, if thirty are good, the book is great.
[tr. McLean (2014)]