Pegs are to be positioned in a trench at 5m intervals at a gradient of 1 in 50 rise, starting at a height of 18.20m ODm, for the first peg. A level was set up and a BS of 2.56m was obtained on a TBM 920.63m OD. What staff reading will be required to position the pegs at 15m and 25m?

Pegs are to be positioned in a trench at 5m intervals at a gradient of 1 in 50 rise, starting at a height of 18.20m ODm, for the first peg. a level was set up and a BS of 2.56m was obtained on a TBM (20.63m OD). What staff reading will be required to position the pegs at 15m and 25m?

TYPO ** sorry