Question

An electric refrigerator rate 350W is used for 8hrs per day. An electric fan rated 750W used for 2hrs per day. Calculate the cost of using these appliances for 30days. It's the cost of 1 unit is RS. 4​

Answer 1

Answer:-

Required cost is Rs.516 .

Explanation:-

It is given that, an electric refrigerator of 350W and a fan of 750W are used for 8 hours and 2 hours per day respectively. Now, we need to calculate the cost of using of these appliances for 30 days at Rs.4/unit.

Energy consumed by the refrigerator per day :-

= Power × Time

= 350 × 8

= 2800 Wh

Energy consumed by the fan per day :-

= Power × Time

= 750 × 2

= 1500 Wh

Total, energy consumed in one day :-

= (2800 + 1500)Wh

= 4300 Wh

Energy consumed in 30 days :-

= 4300 × 30

= 129000 Wh

________________________________

Now, let's convert the total energy consumed from 'Wh' to 'kWh' :-

⇒ 1 Wh = 0.001 kWh

⇒ 129000 = 129000(0.001)

⇒ 129 kWh

Finally, cost of using the appliances :-

= Rs(129 × 4)

= Rs.516

Answer 2

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${\large{\frak{\pmb{\underline{Undertanding \; the \; question}}}}}$

★ This question says that there are two appliances named electric refrigerator and electric fan. The electric refrigerator rate as 350 watts is used for 8 hours per day. The electric fan rated 750 watts used for 2 hours per day. Calculate the cost of using these appliances for 30 days. The cost of one unit is rupees 4.

${\large{\frak{\pmb{\underline{Given \; that}}}}}$

★ There are two appliances named electric refrigerator and electric fan.

★ The electric refrigerator rate as 350 watts is used for 8 hours per day.

★ The electric fan rated 750 watts used for 2 hours per day.

★ The cost of one unit is rupees 4 (for the cost of using these appliances for 30 days).

${\large{\frak{\pmb{\underline{To \; calculate}}}}}$

★ The cost of using these appliances for 30 days.

${\large{\frak{\pmb{\underline{Solution}}}}}$

★ The cost of using these appliances for 30 days = 516 Rupees

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${\large{\frak{\pmb{\underline{Using \; concept}}}}}$

★ Formula to find energy

${\large{\frak{\pmb{\underline{Using \; formula}}}}}$

★ Energy = Power × Time

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${\large{\frak{\pmb{\underline{Full \; Solution}}}}}$

Firstly for the electric refrigerator let us find the energy Let's do it!

~ Finding energy for the electric refrigerator -:

• Power = 350 watts
• Time = 8 hours

➟ Energy = Power × Time

➟ Energy = 350 × 8

➟ Energy = 2800 wh per hour

~ Now let us find for the electric fan let us find the energy. Let's do it too!

~ Finding energy for the electric fan -:

• Power = 750 watts
• Time = 2 hours

➟ Energy = Power × Time

➟ Energy = 750 × 2

➟ Energy = 1500 wh per hour

~ Total energy consumed in one day -:

➟ 2800 + 1500

➟ 4300 wh

~ Energy consumed in 30 days -:

➟ 4300 × 30

➟ 129000 wh

~ Now we have to convert wh into kWh -:

➟ 1 wh = 0.001 kWh

➟ 129000 × 0.001

➟ 129 kWh

~ Now finding the cost of using these appliances for 30 days. It's the cost of 1 unit is rupee 4

➟ 129 × 4

➟ 516 Rupees

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