Note that a change can be an increase or a decrease. For an increase, use a positive number.
For a decrease, use a negative number.
(a) A tram moved downward 27 meters in 9 seconds at a constant rate. What was the change in
the tram's elevation each second?
(b) In a lab, a substance was heated by 4 °C each hour for 36 hours. What was the total change
in temperature?