Question

The normal annual average rainfall at four rain guage stations A, B, C and D are 140, 125 , 115 and 150 cm respectively. During a particular year station D was inoperative and remaining stations A, B and C recorded annual rainfall of 105, 98 and 93 cm respectively. The estimated rainfall at station D would be____cm.

• A. 117.135

Answer 1

The correct option is A 117.135
$\begin{array}{ccccc}\text{Station}& A& B& C& D\\ \text{N(cm)}& 140& 125& 115& 150\\ \text{P(cm)}& 105& 98& 93& P_D=P_x=?\end{array}$




So the normal ratio method will be used.

$\frac{P_x}{150}=\frac{1}{3}[\frac{105}{140}+\frac{98}{125}+\frac{93}{115}]$

$P_D=P_x=117.135cm$