You have been commissioned to determine the proportion of volatile solids (VS) in a substrate that you want to use to produce biogas. The substrate sample you analyze weighs 90 grams, and the crucible you use weighs 120 grams. After drying the sample for 24 hours at a temperature of 105 C, the sample and the crucible weighed together 138.2 g. After annealing at a temperature of 550 C for two hours, the sample and the crucible weighed 127.5 grams. What is the VS of the sample expressed in% of TS? Answer in full % without decimals.