Ok, so I have been in a battle with my stepson over his homework. He is not understanding venn diagrams and we are both in tears. Maybe I am the one not understanding but seriously I need help! What is this answer??? A group of friends went to an amusement park. Ten of them rode the Ferris Wheel, 15 rode the carousel, and 11 rode the roller coaster. Seven of them rode both the Ferris Wheel and roller coaster, 4 rode both the Ferris wheel and carousel, 5 rode both the carousel and roller coaster, and 3 rode all three rides. How many friends went to the amusement park? Ugh! I wish I could explain it to him without all of us getting frustrated!