Here, percentage increase or decrease in the prices of food items are given.

∴ Index number of the item

= 100 + % increase OR

= 100 – % decrease

∴ Suppose, importance of ghee is 1.

∴ the importance of oil is 3 × 1 = 3

and that of rice is 2 × 1 = 2

The importance of wheat and bajri each is double the importance of rice,

∴ the importance of wheat is 2 × 2 = 4

and that of bajri is 2 × 2 = 4

General index number of price

\(I=\frac{\sum IW}{\sum W}\)

\(=\frac{1775}{14}=126.79\)

Hence, price index of a group of five items is obtained 126.79.

Interpretation: There is 26.79 % in the prices of five items of the group.