Amara needs to create a special tasting menu at her restaurant. She needs to select 4 dishes from 7 available dishes and put them in a tasty sequence.How many unique ways are there to arrange 4 of the 7 dishes?
Q. Amara needs to create a special tasting menu at her restaurant. She needs to select 4 dishes from 7 available dishes and put them in a tasty sequence.How many unique ways are there to arrange 4 of the 7 dishes?
Problem Understanding: Understand the problem.Amara needs to select 4 dishes out of 7 and arrange them in a sequence. This is a permutation problem because the order of the dishes matters.
Permutation Formula: Apply the formula for permutations without repetition.The number of ways to arrange k items from a set of n items is given by the formula (n−k)!n! where "!" denotes factorial.Here, n=7 (total dishes) and k=4 (dishes to be arranged).
Calculate n!: Calculate the factorial of n (7!).7!=7×6×5×4×3×2×1
Calculate (n−k)!: Calculate the factorial of (n−k) which is (7−4)! or 3!.3!=3×2×1
Substitute into Formula: Substitute the values into the permutation formula.Number of unique ways = 7!/(7−4)!= 7!/3!
Perform Calculation: Perform the calculation.Number of unique ways =(7×6×5×4×3×2×1)/(3×2×1)The 3×2×1 in the denominator and numerator cancel each other out.Number of unique ways =7×6×5×4=840