Question 495636
first trip:
lisa goes over with 2 people
lisa comes back.
there are 2 people on the other side


second trip:
lisa goes over with 2 people
lisa comes back.
there are 4 people on the other side


third trip:
lisa's dog goes over with 2 dogs
lisa's dog comes back
there are 4 people and 2 dogs on the other side


fourth trip:
lisa's dog goes over with 2 dogs
lisa's dog comes back
there are 4 people and 4 dogs on the other side


fifth trip:
lisa goes over with her dog
nobody comes back
there are 5 people and 5 dogs on the other side


it took 5 trips total.


if the dog was not able to drive the boat, then it would have required the following:


first trip:
lisa goes over with 1 person and their dog.
lisa comes back
1 person and 1 dog is on the other side


second trip:
lisa goes over with 1 person and their dog.
lisa comes back
2 people and 2 dogs are on the other side


third trip:
lisa goes over with 1 person and their dog
lisa comes back
3 people and 3 dogs are on the other side


fourth trip:
lisa goes over with 1 person and their dog
lisa comes back
4 peopleand 4 dogs are on the other side


lisa goes over with her dog
nobody comes back
5 people and 5 dogs are on the other side


it would have taken 5 trips either way.
the crossing was not impossible.
it did not require the dog to know how to operate the boat.


not as far as i can tell.
every trip did not require lisa to operate the boat.
anybody could have done it.
there was no restriction on what person could operate the boat.


5 trips were required either way.
on the last trip, there was no return.
if you count each way as a trip, then 9 trips were required.
5 going and 4 coming back.