Gate 2015 Q45. Samples of copper ores are drawn from locations X1, X2 and X3 as shown in figure below. the values of (%Cu) at sampling locations are given in brackets. The Estimated grade at point X0 using inverse distances weighting is ______ %

Solution :-  Using formula of (IDW) Inverse Distance Weighted Method

\[\large IDW = \frac{\sum \frac{Wi}{Zi}}{\sum \frac{1}{Zi}}\]

\[\large IDW= \frac{\frac{0.022}{2}+\frac{0.011}{1}+\frac{0.033}{3}}{\frac{1}{2}+\frac{1}{1}+\frac{1}{3}}\]

\[IDW = \frac{0.033}{1.83}\]

\[IDW = 0.018\]

IDW = The ore of grade at Xo = 1.8%