# Civil Engineering - Surveying - Discussion

Discussion Forum : Surveying - Section 3 (Q.No. 16)
16.
In case of reduction of levels by the height of instrument method,
∑ B.S. - ∑ F.S. = difference in R.L.S of the first station and last station
∑ (R.L. + I + F.S.) - first R.L = ∑ (H.I. + No. of R.L.s.)
both (a) and (b) above
neither (a) nor (b).
Explanation:
No answer description is available. Let's discuss.
Discussion:
22 comments Page 1 of 3.

Tapendra Bista said:   10 months ago
The Right Answer is option A Because Hight of the instrument = bs - fs = last rl - first rl.
(1)

Deva said:   2 years ago
According to me, A is the right answer.

Uttam said:   2 years ago
Thank you all for explaining the answer.

Dhan Bahadur bist said:   3 years ago
Height of instruments method is;
= Sum Bs - sum fs= last Rl - first Rl.
(1)

Hruaia said:   4 years ago
According to me, A is correct.

ManiSivan said:   4 years ago
Arithmetic check :

Sum of BS - Sum of FS = Last RL - First RL

Arjun m said:   5 years ago
When we are writing as equation format first-last and last- first matters.

But mentioning as the difference of Last RL and First RL /Last RL and First RL is same.

C.KARTHIKEYAN said:   5 years ago