In June , Blackty , received a payment work billed the previous month . The company replanted a dear - cut area of northem Alberta for which it se an invoice for $20000 . At the beginning of the month the company had $ 1,000 of trees for planting . During the month the company purchased $ 4, 000more , and the end of the month it was left with trees that had cost $ 500 . The company's expenses were $ 1000 rent for its office and $ 3000 in other expenses . Amortization on the truck and office equipment was calculated to be $ 500 . The income tax rate is 10% . The expected life of the truck and office equipment when purchased new was 2 years , with no residual value and the amortization expense was based on the straight - line model . The original cost of the truck and office equipment was?