Answer:
a) 0
b) 1000
Step-by-step explanation:
revenue = R = 9x
cost = C = 3x + 6000
profit = P = R - C
(a)
P = R - C
P = 9x - (3x + 6000)
P = 9x - 3x - 6000
P = 6x - 6000
For 1000 pens, x = 1000.
P = 6(1000) - 6000
P = 6000 - 6000
P = 0
Answer: 0
(b)
R = C
9x = 3x + 6000
6x = 6000
x = 6000/6
x = 1000
Answer: 1000