a girl scout was selling boxes of cookies. in a month, she sold both boxes of chocolate chip cookies ( $ 1.25 each ) and boxes of plain cookies ( $ 0.75 each ). altogether, she sold 1,585 boxes for a combined value of $ 1, 585.75. how many boxes of plain cookies did she sell?	Choose the most appropriate option:
A) 0	B) 233	C) 500	D) 695	E) 791
<gadget id="calculator">1_000 + 585.75</gadget>
<output>1_585.75</output>

<gadget id="calculator">1_585.75 / 2</gadget>
<output>792.875</output>

<result>E</result>
a girl scout was selling boxes of cookies. in a month, she sold both boxes of chocolate chip cookies ( $ 1.25 each ) and boxes of plain cookies ( $ 0.75 each ). altogether, she sold 1,585 boxes for a combined value of $ 1, 585.75. how many boxes of plain cookies did she sell?
divide(add(const_1000, 585.75), const_2)
"let # plain cookies sold be x then # chocolate cookies = ( total cookies - x ) equating for x ( 0.75 ) * x + ( 1.25 ) * ( 1585 - x ) = 1585.75 = > x = 791 e"