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? Choose the correct choice from the following answers
A) 0  B) 233  C) 500  D) 695  E) 787
Let #plain cookies sold be X then #chocolate cookies = (total cookies-X)   787quating for X   (0.75)*X +(1.25)*(1585-X)=1587.75   =&gt;x=787   787
<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?