Solve. A mathematical model for the average of a group of people learning to type is given by N(t) = 10 +6 Int, t21, where N(t) is the number of words per minute typed after t hours of instruction and practice (2 hours per day, 5 days per week). What is the rate of learning after 50 hours of instruction and practice? Select one: O A. 0.5 words per minute typed per hour of instruction and practice O B. 0.12 words per minute typed per hour of instruction and practice O C. 0.15 words per minute typed per hour of instruction and practice O D. 0.1 words per minute typed per hour of instruction and practice