A 2 in. × 8 in. × 10 in. iron casting is produced and, after cooling to room temperature, is found to weigh 43.9 lb. Determine
(a) the percent of shrinkage that must have occurred during solidification; and
(b) the number of shrinkage pores in the casting if all of the shrinkage occurs as pores with a diameter of 0.05 in.