Answer:
import java.util.Scanner;
public class num6 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter number of guest");
    int totalGuest = in.nextInt();
        System.out.println("Enter number of slices per guest");
    int slicesPerGuest = in.nextInt();
        System.out.println("How many Slices are on a pizza");
    int slicesPerPizza = in.nextInt(); // Assume each pizza has 5 slices
    double pizzasNeeded;
        //Calculating the pizza Needed
     int totalslicesNeeded  = totalGuest * slicesPerGuest;
     pizzasNeeded = totalslicesNeeded/slicesPerPizza;
        System.out.println(pizzasNeeded);
    }
}
Explanation:
In this program User is required to enter values for the variables totalGuest, slicesPerGuest  and slicesPerPizza
First calculate the totalSlices needed by totalGuest * slicesPerGuest;
The calculate number of pizzas needed by totalslicesNeeded/slicesPerPizza;