The coach of a lacrosse team bought ice cream cones to celebrate a victory. A single-scoop cone was $3 and a double-scoop cone was $5 The coach bought 15 cones and paid $57. A system of equations describing this situation could be written in the form below where s represents the number of single cones andd represents the number of double cones. What is the sum of A, B, C and E?​