A Finite final consists of 50 multiple choice questions. If each question has 5 choices and 1 right answer, find the probability that a student gets an A (i.e. 45 or better) by purely guessing on each question.

A multiple-choice test consists of 5 questions, each question with 4 possible responses(A, B, C, D). A student guesses on each question. Find the probability that the student will guess correctly on at least 1 question.

A student takes a multiple choice test that has 10 questions. Each question has five choices. The student guesses randomly at each answer. Find the probability that more than four of them fail the test.

A bag of marbles contains 4 red, 3 blue, 2 green and 1 yellow marble.  Half of the red and green marbles are glass, and all of the other marbles are polished stone.  What is the probability of selecting: Add the colors together to determine how many marbles are in the bag.  This will become the right side of the answer.  Determine how many marbles exactly fit the specified criteria to find the left side.  Remember to reduce if necessary. A yellow stone marble:  Ratio: ____ : ____ A blue or green stone marble: Ratio:  _____ : _____ Two red marbles in a row without replacement: Ratio:  _____ : _____ Three glass marbles in a row with replacement:  Ratio: _____ : _____