Students in a mathematics class took a final examination. They took equivalent forms of the exam in monthly intervals thereafter. The average score, f(t), for the group after t months was modeled by the human memory function f(t) = 75 - 10 log(t + 1), where 0 ≤ t ≤ 12. Use a graphing utility to graph the function. Then determine how many months elapsed before the average score fell below 65.