"An economy is based on three sectorsdashagriculture, manufacturing, and services. For each unit of output, agriculture requires inputs of 0.20 unit from agriculture, 0.40 unit from manufacturing, and 0.20 unit from services. For each unit of output, manufacturing requires inputs of 0.30 unit from agriculture, 0.20 unit from manufacturing, and 0.20 unit from services. For each unit of output, services requires 0.20 unit from agriculture, 0.30 unit from manufacturing, and 0.30 unit from services. Determine the production levels needed to satisfy a final demand of 0 units for agriculture, 40 units for manufacturing, and 0 units for services."