Bonjour Mary,

In the context of an exam / a test etc, ‘réussir à + noun’ or ‘réussir + noun' mean to pass / to succeed in doing [sth]

‘réussir à + noun’ is used in a more formal context than ‘réussir + noun’, which has become accepted over the years in the French language.

I hope this is helpful.

Bonne journée!