Take the monkey across the river and leave it on the other side.

Go back and take the tiger across the river and leave it on the other side with the monkey.

Take the monkey back to the original side and leave it there.

Take the banana across the river and leave it on the other side with the tiger.

Go back and take the monkey across the river for the final time.

Now you have all 3 on the other side of the river.👏