Problem 1. A class is given a list of 20 study problems from which 10 will be part of an upcoming exam. If a given student knows how to solve 15 of the problems, find the probability that the student will be able to answer,a. all 10 questions on the exam?b. exactly eight questions on the exam?c. at least nine questions on the exam?Problem 2. A class is given a list of 8 study problems from which 5 will be part of an upcoming exam. If a student knows how to solve 6 of the problems, find the probability that the student will be able to answer,a. all 5 questions on the exam?b. exactly 4 questions on the exam?c. at least four questions on the exam?Problem 3. 4 letters and envelopes are addressed to 4 different people. If the letters are randomly inserted into the envelopes, what is the probability that,a. exactly 1 is inserted into the correct envelope.b. at least 1 is inserted into the correct envelope.Hi, Could you solve and give a detailed(emphasize detailed) explanation ofhow to solve the following three problems. What type of problems theyare and how they work.Please provide translation of any unusual mathematical symbols used.Problem 1. A class is given a list of 20 study problems from which 10 will bepart of an upcoming exam. If a given student knows how to solve 15 ofthe problems, find the probability that the student will be able toanswer,a. all 10 questions on the exam?b. exactly eight questions on the exam?c. at least nine questions on the exam?Problem 2. A class is given a list of 8 study problems from which 5 will be partof an upcoming exam. If a student knows how to solve 6 of the problems,find the probability that the student will be able to answer,a. all 5 questions on the exam?b. exactly 4 questions on the exam?c. at least four questions on the exam?Problem 3. 4 letters and envelopes are addressed to 4 different people. If theletters are randomly inserted into the envelopes, what is theprobability that,a. exactly 1 is inserted into the correct envelope.b. at least 1 is inserted into the correct envelope.