Help me please, workbook problem :(

I have to do these work books for a grade but I'm having a really hard time figuring out these questions. Any help is appreciated! Thank you...

1.) The probability distribution of the number of people entering a store each day based on past data is given below. Find the expected number of people for one day. Enter only a number.
Number of people 'n' -> 76, propability of 'n' people -> 0.3
Number of people 'n' -> 84, probability of 'n' people -> 0.2
Number of people 'n' -> 98, probability of 'n' people -> 0.1
Number of people 'n' -> 89, probability of 'n' people -> 0.4

I couldn't find any kind of pattern or anything... It's really confusing for me.

2.) (a + 2b)3 = a3 + 6a2b +... Use the Binomial Theorem to complete the binomial expansion.; enter only the next two terms.
Use the ^ key for exponents; example: 25x^2y+3y^2

3.) (3x + 5)3 = 27x3 + 135x2 + ... Use the Binomial Theorem complete the binomial expansion.; enter only the next two terms.; example: 100x+200

4.) The principal will randomly choose 6 students from a large school to represent the school in a newspaper photograph. The probability that a chosen student is an athlete is 30%. (Assume that this doesn't change.). What is the probability that 4 athletes are chosen? Round your answer to the nearest hundredth.

5.) Wendy takes a multiple-choice quiz that has 20 questions. There are 4 answer choices for each question. What is the probability that she will get at least 2 answers correct by guessing? Round your answer to the nearest hundredth.

I'm sorry I have to ask for help, but I would love and appreciate any help you can provide for me. Thank you again.

Expected number of people = Probability * Number of people
Hence,
Number of people 'n' -> 76, propability of 'n' people -> 0.3 = 76 * 0.3 = 22.8