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For this question the answer is b which is the TR of group 2. If price is the same, my question is why isn't the demand function of group 1 considered? Why is the TR of group 1 omitted?
To sell 45 units to group 2 implies a price of $220-2Q_2=130$. At that price, demand from group 1 is zero. Indeed, the very most any consumer in group 1 is willing to pay is $100$.
Required, but never shown