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, 587.75. how many boxes of plain cookies did she sell? Options:  A) 0  B) 233  C) 500  D) 695  E) 787
<gadget id="calculator">1_000 + 587.75</gadget>
<output>1_587.75</output>

<gadget id="calculator">1_587.75 / 2</gadget>
<output>793.875</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, 587.75. how many boxes of plain cookies did she sell?
divide(add(const_1000, 587.75), const_2)
"let # plain cookies sold be x then # chocolate cookies = ( total cookies - x ) equating for x ( 0.75 ) * x + ( 1.25 ) * ( 1585 - x ) = 1587.75 = > x = 787 e"