Answer:
B) 19.4%
Step-by-step explanation:
It is given that average consumption of electricity by the family is 900 kWh per month. Since, there are 12 months in a year, and we have the average consumption of electricity per month, the total consumption for the year would be:
Total electricity consumed in a year = 900 x 12 = 10800 kWh
Next it is stated that during the summer, the same family uses 2 window-unit air conditioners and each of them uses 350 kWh of electricity per month. So, the total electricity used by both units per month would be:
Electricity used by 2 air conditioners in 1 month = 2 x 350 = 750 kWh
Since, the family uses these air conditioners for 3 month, the total consumption for 3 months would be:
Total electricity consumption for 3 months of 2 air conditioners = 3 x 750 = 2250 kWh.
We have to find what percentage of total annual electricity is used to run the 2 air conditioners for three months of summer. So, we have to find 2250 is what percent of 10800. This can be done as:
[tex]\text{Percentage}=\frac{\text{Value of interest}}{\text{Total Value}} \times 100\%\\\\ =\frac{2250}{10800} \times 100\%\\\\ =19.4\%[/tex]
This means, 2 air conditioners consume 19.4% of the annual electricity.
