2P= 140-Q ---> PD= 70- Q / 2
3P= Q+10 ---> PS= (Q+10) / 3
PD-PS=5 ---> 420-3Q-2Q-20 = 30 ---> 370 = 5Q ---> Q=74
---> PD= 33 ; PS = 28 ; Tax = 5 x 74 = 370 ;
CS = 37x 74 / 2 =1396 ; PS= 28 x 74 / 2 = 1036 ; DWL = 5 x 6 / 2 = 15