question_answer

In a factory, an electric bulb of 400W is used for 3 hours and electric motor of 0.4 horse power is used for 6 hours energy day. Calculate the cost of using the bulb and motor for 30 days, if the cost of electrical energy is 2.50 rupee per unit.

Answer:

               

Electric bulb	Motor
\[{{P}_{1}}=400\,W\]	\[{{P}_{2}}=0.4\,\,hp=0.4\times 746w\]
\[{{t}_{1}}=3\,\,hours/day\]	\[{{t}_{2}}=6\,\,hours/day\]

Total no. of days = 30 Cost per unit = 2.5 rupee Total cost = ? Total cost = Total no. of units × 2.5 rupee?(1) Total no. of units = Total power in kwh in 30 days \[=(0.4\times 0.298\times 6)\times 30\] \[=3\,\,kwh\times 30\] \[=90\,\,kwh=90\,\,units\]