In a pasteurization plant, milk circulates through a pipe that is submerged in two large containers A and B, which are maintained at −10 deg C and 65 deg C, respectively. A certain amount of milk circulates through container A, whose initial temperature is 20deg C. After one minute the temperature of the milk is 10deg C. Five minutes later, the milk is immediately pumped into the other container. After spending four minutes in container B, the temperature of the milk increases by 8deg C. How long, from the beginning of the process, does it take for the milk to reach 40deg C in container B?