2. Staff readings on pegs x and y from X station are 1.755 m and 2.850 m, and from station Y on staff head at Y and X are 0.655 m and 1.560 m. If reduced level of X is 105.5 m, the reduced level of Y is
5. If i is the stadia distance, f is the focal length and d is the distance between the objective and vertical axis of the techeometer, the multiplying constant, is
8. A level when set up 25 m from peg A and 50 m from peg B reads 2.847 on a staff held on A and 3.462 on a staff held on B, keeping bubble at its centre while reading. If the reduced levels of A and B are 283.665 m and 284.295 m respectively, the collimation error per 100 m is