Q. Three students are running a race. How many different ways can they come in first, second, and third?Answer:
Understand the Problem: Understand the problem.We need to find the number of different permutations of three students finishing a race in first, second, and third place. A permutation is an arrangement of all or part of a set of objects, with regard to the order of the arrangement. Since the order in which the students finish the race matters, we are dealing with permutations.
Calculate Permutations: Calculate the number of permutations.The number of permutations of n distinct objects taken r at a time is given by the formula:P(n,r)=(n−r)!n!In this case, we have 3 students and we want to arrange all of them, so n=r=3.
Apply Formula: Apply the permutation formula.Using the formula from Step 2, we calculate:P(3,3)=(3−3)!3!P(3,3)=0!3!We know that 3! (3 factorial) is 3×2×1=6 and 0! (0 factorial) is defined to be 1.So, P(3,3)=16P(3,3)=6
Conclude Solution: Conclude the solution.There are 6 different ways the three students can come in first, second, and third in the race.