Amelia rides her bike to work 60% of the time, and walks 40% of the time. She is late 5% of the time she rides her bike, and is late 10% of the time she walks. One day she shows up late. Since she is late, what is the probability she walked to work?

a, After work Amelia plays basketball and shoots 10 times. What is the chance she makes 4 shots or more?