A piece of iron is heated up in the oven, removed, and set out to cool. The table below shows the temperature of the iron (in degrees Fahrenheit)tminutes after being removed from the oven.

Time (minutes)	0	30	60	90	120	150	180	210	240
Temperature (degrees Fahreinheit)	550	223	114	78	66	62	61	60	60

1. Find the average rate of change from 90 minutes to 150 minutes. Round your answer to two decimal places and write out units, using / to represent per.

average rate of change=

1. Find the average rate of change from 30 minutes to 210 minutes. Round your answer to two decimal places and write out units, using / to represent per.

average rate of change=