If absolute levels of rails at the consecutive axles A, B, and C separated by 1.8 metres are 100.505 m, 100.530 m, and 100.525 m respectively, the unevenness of rails, is

ANS:A - 0.065 m

@All.

U= (a+b)/2 - d.

Where a and b are the absolute levels of the 2 end axles and d is the absolute level of the middle axle.
Now the problem here is that the question here has given incorrect data. The book that this question has been copied from had actually given the middle value as 100.580 which has been misprinted as 100.530 here.

If you put the middle value as 100.580 in the above formula you will get the answer exactly.
Take a=100.505.
b=100.525.
d=100.580.
Now solve you will get 0.065 m as the answer exactly.