(3/4) x ($280) = $210
Bill can't afford a new Bose radio.
Maybe some other solution to Bill's dilemma
can be found:
-- Bill could buy a more cost-effective radio.
-- Mia could buy the Bose radio and give it to Bill.
-- Mia could buy the Bose radio and sell it to Bill for $210.
-- Mia could buy the Bose radio for $280, then Bill could buy Mia
for $210, and they could listen to the Bose radio together.