The entire ride takes about twenty minutes is the entire ride simple or complete subject or simple or complete predicate

The entire ride is the complete subject of the sentece. This implies all the words that describe who or what is the sentence is about. In this case, the action is take and we know that is about the ride, so the subject is ride.

type of error:

the error in the sentence is a "dangling modifier". a dangling modifier is a phrase, word or clause that "dangles" because there is not target to modify. in this case, "after mopping the floor" is the dangling modifier since it has no word to modify. the noun "house" cannot mop the floor; therefore there is a mistake in the writing of the sentence.

it translates into:

read the letter of your pen pal. write and answer 3 questions.