20. An on-line clothing retailer charges shipping costs according to the following formula 2n +5.5 if 1En 25

20. n on-line clothing retailer charges shipping costs according to the following formula 211+5.5 if 1 Sn <25 S(n) = if n 225 where n is the number of clothing items and S(n) is the shipping cost in dollars. a. What is the cost to ship 15 clothing items? b. What is the significance of the formula S(n) = 0 for n 25?