Quantity of trees Q	Variable cost VC	Total cost TC	Marginal cost of tree MC = ΔTC/ΔQ	Marginal revenue of tree MR	Net gain of tree = MR – MC
0	$0	$140
			$16	$18	$2
10	160	300
			6	18	12
20	220	360
			8	18	10
30	300	440
			12	18	6
40	420	560
			16	18	2
50	580	720
			20	18	−2
60	780	920
			24	18	−6
70	1,020	1,160