(a) It is noted that 8% of SP students are left handed. If 20 (TWENTY) students are randomly selected, calculate the

The problem is: How many people are there in SP?

this is a math question

 It is noted that 8% of SP students are left handed. If 20 (TWENTY) students are randomly selected, calculate the

                 i. probability that none of them are left-handed, 

                 ii. probability that at most 2 are left-handed, 

                 iii. standard deviation for the number of left-handed students 

(b) If 50 (FIFTY) classes of 20 (TWENTY) students are randomly selected, what is the probability that 10 (TEN) classes have no left-handed students? 

this is a  quantitative analysis work
but i dont know how to use the formula to do