Henry is on his way to give a lecture on elliptic functions at universaty. He didn't have time to prepare properly, so he decides to buy a cup of coffee to give him an extra boost before he starts to prepare. As he gets his coffee, he sees that there are 2 more hours until the lecture begins. Henry needs at least 90 minutes to go over his lecture to fine-tune the last details. He is very enthusiastic about coffee and refuses to drink coffee that does not hold the ideal temperature. Henry has realized that, according to researchers at the University of Texas, the ideal temperature for coffee is 58 C. He learns from the barista that the coffee he bought is incandescent and holds 100 C. According to the barista, the coffee becomes lukewarm (37 C) after 1 hour. The temperature in all rooms at university the day is 21 C. Henry drinks the coffee as soon as it reaches the ideal temperature. Is it enough time for Henry to fine tune the last details of his lecture before he gives the lecture?

(Hint: Use Newton's law of cooling to set up an initial value problem and then solve the initial value for the problem.