Marisa is buying a vase of red roses for Mother's day. The florist charges $12.00 for a vase Marisa selected plus $4.75 per rose. Determine an equation to represent the cost of the bouquet, C, in terms of the number of roses in the bouquet, r. If Marisa has saved $55 to get her Mother's Day bouquet, how many roses can she have the florist put in the vase?​