Suppose that two firms, X and Y$,$ face the following abatement costs, where A is the abatement $($pollution reduction$)$ chosen by the firm:

MACX $=1\mathrm{.}2$AX$,$ MACY $=0\mathrm{.}3$AY

TACX $=0\mathrm{.}6$AX$2$ TACY $=0\mathrm{.}15$AY$2$

Further assume that the combined abatement standard is $40$ units for both firms.