http://codingbat.com/prob/p132134

p132134.java

public boolean in3050(int a, int b) {
  Range range3 = new Range(30, 40);
  Range range4 = new Range(40, 50);
  return range3.contains(a,b) || range4.contains(a,b);
}

class Range {
  int min;
  int max;
  public Range(int min, int max) {
    this.min = min;
    this.max = max;
  }
  public contains(int x, int y) {
    return contains(x) && contains(y);
  }
  public contains(int x) {
    return x >= min && x <= max;
  }
}

Solution:

public boolean in3050(int a, int b) {
  return (
    (a >= 30 && a <= 40)
    &&
    (b >= 30 && b <= 40)
    ) || (
    (a >= 40 && a <= 50)
    &&
    (b >= 40 && b <= 50)
    );
}