A differential manometer is used to measure the difference in pressure at points A and B in terms of specific weight of water, W. The specific gravities of the liquids X, Y and Z are respectively s1, s2 and s3. The correct difference {(PA/W)-(PB /W)} is given by

Option (A)
h3s2 - h1s1 + h2s3
Option (B)
h1s1 + h2s3 - h3s2
h3s1 - h1s2 + h2s3
h1s1 + h2s2 - h3s3
Correct Option:
Question Solution:
Staring from point A and writing manometric equation
(PA/W) + h1S1 - h2S3 - h3S2 = PB/W)
\ (PA/W) – (PB/W) = h2S3 - h1S1 + h3S2