How do I format the output for average age to round to the nearest 10th? Also, how do I get the oldest age to be correct? (Java)

package cis254assignments;

import java.util.Scanner;

public class A6_3 {

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

final int AGE_GROUP_A = 18; // age limit set to 18

final int AGE_GROUP_B = 30; // age limit set to 30

final int AGE_GROUP_C = 40; // age limit set to 40

final int AGE_GROUP_D = 60; // age limit set to 60

int age = 0;

int ageGroupA = 0; // variable to store count of age group 0-18

int ageGroupB = 0; // variable to store count of age group 19-30

int ageGroupC = 0; // variable to store count of age group 31-40

int ageGroupD = 0; // variable to store count of age group 41-60

int ageGroupE = 0; // variable to store count of age group over 60

int sumAges = 0;

int attendeeCount = 0;

int youngest = 0;

int oldest = 0;

int ave;

int popcorn = 0;

int soda = 0;

int both = 0;

String preference;

System.out.print("Enter age of attendee (negative number to quit): ");

age = input.nextInt();

while (age >= 0) {

sumAges += age;

attendeeCount++;

youngest = age;

oldest = age;

System.out.print("food preference (enter 'p' fpr popcorn, 's' for soda, 'b' for both): ");

preference = input.next();

if (age < youngest)

youngest = age;

else if (youngest < age);

ag;

if (age <= AGE_GROUP_A)

ageGroupA++;

else if (age <= AGE_GROUP_B)

ageGroupB++;

else if (age <= AGE_GROUP_C)

ageGroupC++;

else if (age <= AGE_GROUP_D)

ageGroupD++;

else if (age > AGE_GROUP_D)

ageGroupE++;

if (preference.equals("p"))

popcorn++;

else if (preference.equals("s"))

soda++;

else if (preference.equals("b"))

both++;

System.out.print("Enter age of attendee "

+ "(negative number to quit): ");

age = input.nextInt();

}

System.out.println("age 0 to 18: " + ageGroupA);

System.out.println("age 19 to 30: " + ageGroupB);

System.out.println("age 31 to 40: " + ageGroupC);

System.out.println("age 41 to 60: " + ageGroupD);

System.out.println("over 60: " + ageGroupE);

System.out.println();

System.out.println("Food preference popcorn: " + popcorn);

System.out.println("Food preference soda: " + soda);

System.out.println("Food preference both: " + both);

System.out.println("The average age was " + sumAges / attendeeCount);

System.out.println("The youngest person in attendance was: " + youngest);

System.out.println("The oldest person in attendace was: " + oldest);

{

}

}

}