Question 1101756
He buys {{{ 1440*12 }}} pens
at {{{ 2.5/12 }}}
----------------------------
{{{ ( 2.5/12 )*( 1440*12 ) = 2.5*1440 }}}
{{{ 2.5*1440 = .25*14400 }}} is his cost
------------------------------------
{{{ .25*12*1440 - .25*14400 }}} is his profit
{{{ .25*1440*( 12 - 10 ) = .25*2880 }}}
{{{ 720 }}} dollars is his profit
---------------------------
check the math