Within minutes, they had their equipment packed. They were off!

Combined sentence: Within minutes, they had their equipment packed and were off!
Does the combined sentence use a compound subject, compound verb, or
compound object?

Please see my answer below.

It's a compound sentence, so has two subjects and two verbs. As written, the subject of the second clause is implied, but is "they". This sentence or sentences has/have no direct object. There is, however, a misplaced modifier.

Sorry, that is not all correct. "equipment" is the direct object of the verb "packed".

The combined sentence, "Within minutes, they had their equipment packed and were off!" does not have a compound subject, compound verb, or compound object.

To understand this, let's break down the sentence:

1. "Within minutes" is a prepositional phrase that functions as an adverb, indicating the time frame.
2. "They had their equipment packed" is a complex sentence in which "they" is the subject, "had" is the main verb, and "their equipment packed" is the object of the verb.
3. "And" is a coordinating conjunction that connects the two independent clauses.
4. "Were off!" is a simple sentence in which "they" is the subject and "were off" is the verb phrase.

In conclusion, there are no compound elements in the combined sentence.