Note that the STA $14+00$ is given, however it is not used as the problem as the station are given STA $11+00$ to STA $13+00.$ Use the Average End Area Method; set up a table to express the calculation steps; solve for the requested information. See FEHB, and use the FE Handbook and search for the information.

$\backslash$table$[[$Stationing$,\backslash$table$[[$Distance$],[(ft)$

Do you know why in finding cut vomime between station you have to find the verage like here at station $12+00$ where its $350+150/2$