Tammie is 6 years older than her younger sister. The average age of the two girls is 12 years old. <hr> Tammie is <input min="0" type="number" id ="imp5pg153q9_1" class="lineinput" placeholder="?" /> years old and <br>her younger sister is <input min="0" type="number" id ="imp5pg153q9_2" class="lineinput" placeholder="?" /> years old.