Josalmina Company is a pure monopolist with fixed costs of $200. The following revenue and cost information are relevant to its operations:

Unit Marginal Output Price Cost

1 $400 $160

2 380 145

3 360 130

4 340 115

5 320 130

6 300 145

7 280 160

8 260 185

9 240 210

10 220 235

11 200 260

12    180   285

Josalmina’s Marginal revenue rate is at its maximum at what output quantity?