Answer: hello your question lacks some data hence I will be making an assumption to help resolve the problem within the scope of the question
answer:
≈ 95 units ( output level )
Explanation:
Given data :
P = 2000 - Q/10
TC = 2Q^2 + 10Q + 200 ( assumed value )
The output level where a purely monopolistic market will maximize profit
at MR = MC
P = 2000 - Q/10 ------ ( 1 )
PQ = 2000Q - Q^2 / 10 ( aka TR )
MR = d (TR ) / dQ = 2000 - 2Q/10 = 2000 - Q/5
TC = 2Q^2 + 10Q + 200 ---- ( 2 )
MC = d (TC) / dQ = 4Q + 10
equating MR = MC
2000 - Q/5 = 4Q + 10
2000 - 10 = 4Q + Q/5
1990 = 20Q + Q
∴ Q = 1990 / 21 = 94.76 ≈ 95 units ( output level )