Final answer:
The first sentence is a compound sentence as it contains two independent clauses joined by a coordinating conjunction. The second sentence is a simple sentence with one main clause and additional information that does not create another clause.
Step-by-step explanation:
In the sentences provided, we need to determine whether they are simple, compound, or complex sentences. A simple sentence has one main clause, while a compound sentence contains at least two independent clauses joined by a coordinating conjunction. A complex sentence contains one independent clause and at least one dependent clause.
The sentence 'She highlighted the main points in red, but the audience could not read the text' consists of two independent clauses joined by the conjunction 'but,' making it a compound sentence. On the other hand, the second sentence 'Business school graduates are considered ideal candidates in some companies that hire them as consultants.' is a simple sentence with a single main clause and additional information that does not form a separate independent or dependent clause.