Answer:
630,630 different arrangements are possible for the given laptops.
Step-by-step explanation:
Total number of laptops = n = 15
Number of identical Dell laptops = 6
Number of identical Chromebooks = 4
Number of identical Mackbooks = 5
We have to find in how many ways can the laptops be arranged. Number of arrangement of objects is calculated using Permutations as the order of objects matter during the arrangement. The formula to calculate the number of possible arrangements when there are similar objects is given as:

Here n is the total number of objects and a,b, and c represent the number of identical objects. Using the given values we get:

This means 630,630 different arrangements are possible for the given laptops.
Answer:
the truth is that I do not understand your way of expressing yourself but you can talk the truth is that I don't understand your way of expressing yourself but you can speak the language with me in Spanish ok
Total students = 15+21=36, so the probability of choosing a girl is 21/36, which reduces to 7/12.
Total freshmen = 12+15=27, so the probability of choosing a freshman is 27/36, which reduces to 3/4.
3(n+2) ← algebraic expression