On January 22 in 1943, the town of Spearfish, South Dakota, set the record for the world's fastest
temperature change.
At 7:30 a. m., the temperature was -4°F.
By 7:32 a. m., the temperature was 45 °F.
By 9:00 a. m. the same day, the temperature was 54 °F.
By 9:27 a. m., the temperature was -4 °F.
How many degrees did the temperature change each
minute from 7:30 to 7:32?
Make sure to show whether the change was positive or
negative.