In a group of five friends: Alice, Bob, Charlie, David, and Eva, Alice is taller than Bob but shorter than Charlie. David is shorter than Eva but taller than Bob. Who is the tallest among them?
In a class of students, John is older than Sarah but younger than Mike. Lisa is older than John but younger than Sarah. Who is the youngest among them?
In a class of students, some are studying Mathematics, some are studying Science, and some are studying both. If 10 students study Mathematics, 8 students study Science, and 4 students study both, how many students study only Mathematics?