sentence2: At that rate, he would have to work for approximately 22 years to pay for his education (that is, of course, only taking into account the official credit hours of the program, and excluding the cost of books, allowance, and added registration fees).
sentence1: بهذا المعدل سيحتاج لأن يعمل 22 عاماً حتى يتمكن من تسديد رسوم دراسته (فقط في حال استثناء تكاليف الكتب، المصروف، ورسوم التسجيل).