1. A cup of tea is placed on a table. At a time of t minutes after being placed on the table, its temperature in degrees Celsius is given by T = 20 + Ae-kt Where A and k are positive constants. The initial temperature of the tea was 70C. a) Find the value of A b) The tea takes 4 minutes to decrease in temperature from 70C to 50C. Show that k = 1 In in (33).