Answer:
Hercules and Pedro train together for the Olympics.
Explanation:
The subject-verb agreement refers to the agreement of the subject(s) and the verb(s) in a sentence in number. This means that a singular subject must use a singular verb while a plural subject must use a plural verb.
In the given sentence, the subject is plural "Hercules and Pedro" while the verb used is singular "trains". This is wrong for a singular subject will have a singular verb and a plural subject will have a plural verb.
So, the error of subject-verb agreement is in the "Hercules and Pedro trains". The correct subject-verb agreement will be-
Hercules and Pedro train together for the Olympics.
