ASP.net MVC 5 C# returning the double from within IF statement

how do i access the double from within the IF statement

 [HttpPost]
    public ActionResult Iflexcst([Optional] float Quan, [Optional] float kammid, [Optional] float kammod, [Optional] float SpacerInnerDim, [Optional] float SpacerOuterDim, [Optional] float WashOuterDim, [Optional]float IsoWashInnerDim, [Optional]float SteelWashInnerDim, [Optional] float SteelWashQuan, [Optional] float IsoWashQuan, FormCollection form)
    {
        //other functions removed
        if (WashOuterDim <= 43.6)
        {

            double washerSerrTime = 0.6;
            double SerrWasherRun = (washerSerrTime * IsoWashQuan) * (1 / 60);
            ViewBag.SerrWasherRun = SerrWasherRun;

            double SerrWasherRunPrice = ((SerrateSetup / Quan) + washerSerrTime) * serrateRate;
            ViewBag.SerrWasherRunPrice = SerrWasherRunPrice;

        }

        if (WashOuterDim > 43.6)
        {


            double washerSerrTime = 0.833;
            double SerrWasherRun = (washerSerrTime * IsoWashQuan) * (1 / 60);
            ViewBag.SerrWasherRun = SerrWasherRun;

            double SerrWasherRunPrice = ((SerrateSetup / Quan) + washerSerrTime) * serrateRate;
            ViewBag.SerrWasherRunPrice = SerrWasherRunPrice;


        }


        // Adds together all costs 
        float Price = (float)SerrWasherRunPrice;

It recommends creating a getting and setting for "SerrWasherRunPrice" or making it a public variable, but both these solutions give me conflicts with another declaration.