Barbara has two business assets that were either wholly or partially destroyed during a tornado. One was a truck with a basis of $34,000 and a market value of $30,000 before the tornado and a value of $15,000 after. The other was a storage and utility building with a basis of $40,000, a market value of $35,000 before the tornado, and no value after due to total destruction. She received $50,000 of insurance proceeds for these two damaged assets. (Topic 5)

What is the amount of her deductible business casualty loss?