Some 200 W bulbs are used for 5 hours every day. if the cost of electricity at the rate of Rs 5 per kilowatt hour is Rs 750 for the month of June, then find the no of bulbs used
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Hello Mate!
Month of june = 30 days.
So, for using x number of bulbs for a month or 30 days it cost Rs 750.
Then for 1 day it will cost = Rs 750/30 = Rs 25
Then for 1 hr it will cost = Rs 25/24 = Rs 1 ( approx ).
Now, each bulb consume 200 W in 5 hrs
In 1 hr it will consume = 200/5 or 40 W
Since 1 W = 1/1000 kW
40 W = 40/1000 kW or 0.04 kW
Now, x number of bulbs will consume 0.04 kW energy per hour which cost Rs 1 at the rate of Rs 5 per kW.
Cost of consuming energy = 0.04x × Rs 5
Cost of consuming energy = Rs 1
1 = 0.04x × 5
1 = 0.2x
1/0.2 = x
5 bulbs = x
Hence 5 bulbs are used.
Have great future ahead!
Month of june = 30 days.
So, for using x number of bulbs for a month or 30 days it cost Rs 750.
Then for 1 day it will cost = Rs 750/30 = Rs 25
Then for 1 hr it will cost = Rs 25/24 = Rs 1 ( approx ).
Now, each bulb consume 200 W in 5 hrs
In 1 hr it will consume = 200/5 or 40 W
Since 1 W = 1/1000 kW
40 W = 40/1000 kW or 0.04 kW
Now, x number of bulbs will consume 0.04 kW energy per hour which cost Rs 1 at the rate of Rs 5 per kW.
Cost of consuming energy = 0.04x × Rs 5
Cost of consuming energy = Rs 1
1 = 0.04x × 5
1 = 0.2x
1/0.2 = x
5 bulbs = x
Hence 5 bulbs are used.
Have great future ahead!
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