Is it possible to limit the query and remove to certain number?

I have an issue with memory usage when doing a remove. No problem to query

Matched rows: 1,551 out of 3,767 total.

Page 1 of 63 (25 post per page)

After the query, i click removed all and error appears due to memory limit. It only remove to certain pages.

When i run query again,

Matched rows: 1,365 out of 3,787 total.

Page 1 of 55 (25 post per page)

How to limit the query to let say 50 posts and it should be no issue.

Please help.

Thank you.