The Fitness Shop is considering ordering a special model exercise machine. Each unit will cost the shop $$350,$ and it will sell for $$750.$ Any units not sold at the regular price will be sold at the year$-$end model clearance for $$250.$ Assume that demand follows a normal probability distribution with $\backslash$mu $=40$ and $\backslash$sigma $=10.$ What is the recommended order quantity?