could you help me with this

Benzene is a toxic chemical used in the manufacturing of medicinal chemicals, dyes, artificial leather, and linoleum. A manufacturer claims that its exit water meets the federal regulation with a mean of less than 7980 ppm of benzene. To assess the benzene content of the exit water, 10 independent water samples were collected and found to have an average of 8.036 ppm of benzene. Assume a known standard deviation of 81 ppm. Give the test value used for the Hypothesis test that would test the manufacturers claim