Answer :
he spend: 1440*2.5=3600
he earn: 0.25*1440*12=4320
[because he sells 0.25/each and buy 1440 dozen so 1440*12]
4320-3600=720
he earn: 0.25*1440*12=4320
[because he sells 0.25/each and buy 1440 dozen so 1440*12]
4320-3600=720