Direction (): Given below is the information about wind mills in four different villages Attalur, Bodanam and Chehra and Dumri.
Number of wind mills in villages Attalur, Bodanam, Chehra and Dumri are 24, 20, 15 and 12 respectively. Electricity units produced in one week by one wind mill when they operate with maximum efficiency in village Attalur, Bodanam, Chehra and Dumri is 2 lakh units/week, 80000 units/ week, 1 Lakh units/week and 1.5 Lakh units/week respectively. Number of houses in each village Attalur, Bodanam, Chehra and Dumri are 540, 240, 150 and 350 respectively. Total units produced are consumed equally by each house in the village.

→Different number of winds mills operates in four different weeks of a given month.
In first week number of wind mills operative in village Attalur, Bodanam, Chehra and Dumri are 75%, 50%, 40% and 75% respectively out of the total number  of wind mills.
In second week it is 50%, 75%, 60% and 50% respectively.
In third week it is 75%, 100%, 80% and 50% respectively and in the fourth week it is 100%, 50%, 60% and 75% respectively.
→Further, given below is the three ranges of efficiency of a wind mills (electricity produced in number of unit/week by one mill)

Three wind mills also operate on different levels
→level 1 : Consider upper limit of range of efficiency
→level 2 : Consider mid of range of efficiency
→level 3 : Consider the lower range of efficiency
Eg. If a wind mill is operative at efficiency 2 then its level 2 efficiency will be =(45+55)/2 =50%
Its level 1 efficiency will be 55% And, Its level 3 efficiency will be 45%