Question

A washing machine rated 300 W is operated one and half hour/day. If the cost of unit of power is $Rs.3.50,$ find the cost of operating a washing machine for the month of september

• A. ₹ 27.90
• B. ₹ 35.25
• C. ₹ 47.25
• D. ₹ 55.90

Answer 1

The correct option is C ₹ 47.25

Energy consumed by the washing machine (Per day)$=P\times t=\frac{300}{1000}\times \frac{3}{2}=\frac{9}{20}kWh$
A unit of power for homes is calculated in terms of kWh, therefore
Total energy consumed by the washing machine for the month of september $=\frac{9}{20}\times 30=\frac{27}{2}kWhCost=\frac{27}{2}\times 3.50=47.25Cost=47.25$