When a singular noun or pronoun is connected with another noun or pronoun by using words like with, as well as, besides, together with, no less than and other similar expressions, the verb is singular.
The shop, with its articles, was burnt down. (NOT The shop, with its articles, were burnt down.)
The ship, with its crew, was saved.
Silver as well as gold is a precious metal.
The father as well as his sons is industrious.
No one, besides James, knows it.
Kate, and not you, has won the prize.
James, together with his friends, was present.
Notes
When two subjects are joined by as well as, the verb agrees in number and person with the first one.
When one of the subjects joined by or or nor is plural, the verb must be plural, and the plural subject should come close to the verb.
Neither the old man nor his sons are willing to sell the cow. (NOT Neither the old man nor his sons is willing to sell the cow.) (NOT Neither his sons nor the old man is willing to sell the cow.)
When a plural noun denotes a particular amount or quantity considered as a whole, the verb is usually singular.
Hundred cents is equal to one dollar.
Two thousand dollars is a large sum to lose.
Ten miles is a long distance to cover in an hour.
