Answer:
-80cm/sec
Explanation:
It is given that Joe was being exposed to an electro magnet shrinking machine.
Because of this his height started decreasing.
The decrease was at a constant rate per second is given.
In 1.5 seconds, the height decreased by 120 cm.
Since given as constant decrease per second we find that this is direct variation of height over second.
variation per second =
Change in each second would be with negative sign indicating decrease