Given,
The turkey was cooked in the oven for 3 hours.
The internal temperature rose from 30 degress F to 156 degrees F.
Average rise in temperature per hour = Total rise in temperature/ total number of hours
Average rise in temperature = 156 degrees F – 30 degrees F= 126 degrees F
Total number of hours = 3 hours
Average rise in temperature per hour = 126 degrees F/3 hours= 42 degrees F/hour