Riya Khatri, contract negotiator for Nebula Airframe Company, is currently involved in bidding on a follow$-$up government contract In gathering cost data from the first three units, which Nebula produced under a research and development contract, she found that the first unit took $2,000$ labor hours, the second took $1,800$ labor hours, and the third took $1,692$ hours. Use Exhibit $6\mathrm{.}5.$

In a contract for three more units, how many labor hours should Khatri plan for?

Note: Round your answer to the nearest whole number.

Answer is complete but not entirely correct.

$\backslash$table$[[$Number of labor,$3,171x,$hours$]]$