Three independent lines of
levels are run from BM1 to BM2. Route A is 6
km long, route B is 4 km long and route C is 8
km long. By route A, BM2 is 82.27 m above
BM1, by route B, BM2 is 82.40 m above BM1
and by route C, BM2 is 82.10 m above BM1.
20. Compute the probable difference in
elevation between BM1 and BM2.
a. 82.29 m c. 82.56 m
b. 82.95 m d. 82.63 m