BrainDen.com - Brain Teasers  # Silas

Members

1

## Everything posted by Silas

1. For the bowl with 2 poisonous apples out of 5, and you have to eat 3, there are 3 possible ways to die: The first way to die is by eating 2 poisonous apples in a row. The first time there's a 2/5 chance to eat a poisonous apple, which reduces to a 1/4 chance to eat a second one. Multiply these two together: (2/5)*(1/4) = 10% Second way to die is if you eat one good apple and then two bad ones: (2/5) * (2/4) * (1/3) = 6.6% Third way to die is if you eat one bad one, then a good one, and then a bad one: (2/5) * (1/4) * (1/3) = 3.33% Add these probabilities together, 10% + 6.6% + 3.33% = (Basically) 20% This means that the chance of dying is 20%, so a 80% chance of survival. For the second bowl there is only one way to die, and that's if you eat 2 bad ones in a row: (3/5) * (2/4) = 30% So that means there's a 30% chance of death and a 70% chance of survival, respectively. I can't figure out how people get to it being 70% for both.
×

• #### Activity

• Riddles
×
• Create New...