Answer:
Decreasing by 30 per week
Step-by-step explanation:
[tex]q = 0.2p^2 + 2p[/tex]
[tex]\frac{dq}{dt}=0.4p \frac{dp}{dt} + 2\frac{dp}{dt}[/tex]
[tex]\frac{dq}{dt}=(0.4p + 2)\frac{dp}{dt}[/tex]
At p=70, [tex]\frac{dp}{dt}=-1[/tex]
[tex]\frac{dq}{dt}=(0.4X70 + 2)(-1)[/tex]
[tex]\frac{dq}{dt}=-30[/tex]
The number supplied is decreasing by 30 per week.