How does IMC conduct its business ? Graph of a long call ? what is the profit if underlying keeps increasing ? what is loss ? Graph of a short put ? same question. Why do people use these puts with such a small profit ? How long would it take to swim from amsterdam to new york ? If getting a boy and a girl is 50% chances. What is the chance that the family that has a boy, also has a second boy ? You have a 4x4 grid, and three balls. If you manage to get "at least" 2 balls in the same row/column, you win. What is the probability to win ?