Please help I do not understand this word problem.

The time that it takes a carpenter to build a shelving unit is given by the function T(x) = 35 + ce kx minutes, where x is the number of units that the carpenter has made before. It takes the carpenter 47 minutes to build the first shelving unit (x = 0) and 36 minutes to build the twelfth unit. How long will it take the carpenter to build the sixteenth unit? Round your answer to the nearest tenth of a minute. Answer Tables Keypad How to enter your answer (opens in new window) Keyboard Shortcuts