A=2piR
so 144pi=2piR
solve and you get R=72
so D= 144 ft
10,000 of the endangered birds would be left
The cost of manufacturing
units is
, where
cost per unit and
fixed cost.
Given that

Subtract the second equation from the second,

The variable cost per unit is
.
A=2-b
2-b/b=3
2-b=3b
B=1/2
A=3/2
A-b=3/2-1/2=1
Answer is 1