Can you explain on paper for better understanding?

1. How many ways can 4 people be arranged in a line for a photograph if there are 8 people in a group to pick from? C /3 2. How to find the sum of the 20th row in the Pascal triangle? Expalin C /3 C /3 4. One card is drawn from well shuffled 52 cards Explain and find the probability of getting a a) a king of red color C /6 b) a face card c) the queen of diamonds. 5. There are 140 students in a class, 52 are in biology, 71 are in Chemistry, 40 are in Physics, 15 are taking both Chemistry and Biology, 8 are taking Chemistry and Physics , 1 1 are taking biology and Physics, 2 are taking all 3 Sciences, How many students are not in any courses. Find and explain. Thinking /5 1. How many Students are in only Physics 2. How many are only in Biology