Home arithmetic

Subject: Compulsory Maths

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Home arithmetic is simply the arithmetic that is used for the services used in our daily life.

Home arithmetic

We carry different economic activities within our home too such as payment of electricity bill, water bill, telephone bill, etc. Currently, we can find such bills using the information and communication technology (ICT). For example, bill of public switched telephone network can be found by dialing1601.


Electricity Bill

Nepal Electricity Authority (NEA) charges the bill of electricity that public uses at their home. Bills are charged accordance to a capacity of meter used and a number of units consumes monthly. The NEA meters used in our home are from 220 volts to 400 volts.

Electricity charge as per the rule of electricity

Capacity of meter Unit consumed Amount
5 Ampere upto 20 Rs 80
6 to 15 Ampere upto 50 Rs 365
16 to 30 Ampere upto 100 Rs 795
31 to 60 Ampere upto 200 Rs 1765

Energy cost as of 2071/72

Rs. 80 at the rate of Rs. 4 per unit up to 50 units

Rs. 7.30 per unit from 50 to 150 units

Rs. 9.50 per unit 150 to 250 units

Rs. 11.00 above 251

Some of the important information to the electricity consumer:

  • If the meter reader cannot read the meter for three times then, NEA can disconnect the electricity supply at any time.
  • The middle number of the consumer ID denotes the day of meter reading.
  • If the bill is paid within 7 days of reading, 3% discount is given to consumers.
  • The bill is to be paid within 22 days of billing.
  • It the bill is paid within 23 to 30 days of billing 5% charge is added.
  • It the bill is paid within 31 to 40 days of billing 10% charge is added.
  • It the bill is paid within 41 to 60 days of billing 25% charge is added.
  • If the bill is not paid until the 60 days of billing, the electric can be disconnected at any time by NEA authorities without any prior notice.


Water Bill

Water consumption is measured in terms of units. The unit of water consumed is measured by Flow meter. Nepal Water supply corporation (NWSC) sends the water bill every month. In Kathmandu Upatekya Khanepani Limited (KUKL) sends the water bill every month to its consumer.According to Nepal Water Supply Corporation, Tariff provided to all branch are as follow:

According to Nepal Water Supply Corporation, Tariff provided to all branch are as follow:

Pipe size (inch) Minimum consumption (litre) Minimum cost (Rs.) with meter For more consumption cost per unit (Rs.) with meter Main tap charge (Rs) without meter Branch tap charge (Rs) without tap
1/2" 10 units 110 25 560 200
3/4" 27 units 1490 40 3360 1600
1" 56 units 3420 40 9200 2700
1.5" 155 units 9600 40 20700 6500
2" 320 units 21600 40 42300 12000
3" 881 units 49500 40 131400 33000
4" 1810 units 97200 40 250200 62000

1 units mean 1000 litre of water consumption.

50% of water cost is charged a sewerage service charge.

Telephone Bill

The cost of telephone depends upon the number of calls that we make. Telephone company records the number of calls within their database system. Nepal Telecom Company (NTC) records the telephone bill and we should pay it monthly.

Telephone charge rate as per the rule of Nepal Telecom(NTC).

Rs.200 for a minimum of 175 calls Rs.1 per call above the minimum call.

Scheme of payment

Call charge = minimum call charge (C) + additional no. of calls (n) * addtional call rate (r)

i.e. call charge = C+n*r

Telecome service charge (TSC) = 10% of call charge

Value added tax (VAT) = (C + TSC)* 13%

Total amount = Call charge (C) + TSC + VAT

Note: Fine is added to the total bill according to company rule.

Taxi meter

According to the certain rule imposed by government authority, the taxi fare is charged. The meters of taxi are provided and regulated by Department of Transport Management together with Nepal Bureau of Standard and Metrology (NBSM).

According to the current rule, the taxi users should pay the bill as mentioned below:

Time Minimum fare Rate per 200 m distance
Morning 6:00 am to Evening 9:00 pm Rs. 14 Rs. 7.20
Evening 9:00 pm to Morning 6:00 am Rs.21 Rs. 10.80

- Source: Department of Transport Management

Nepal Bureau of Standard and Metrology


Things to remember
  • Home arithmetic is mainly used in our daily life for our household purpose. 
  • It includes every relationship which established among the people.
  • There can be more than one community in a society. Community smaller than society.
  • It is a network of social relationships which cannot see or touched.
  • common interests and common objectives are not necessary for society.
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Home Arithmetic
Questions and Answers

Here, Consumed units of Baisakh=(1250-1050)=200 units

Consumed units of Baisakh=(1250-1050)=200 units

Minimum charge up to 20 units= Rs.80

Additional units =(200-20)=180 units

Charged of additional units =180× Rs.7.30 = Rs 1314

∴Total charge = Rs. 80 + Rs 1314

= Rs.1394 Ans


Consumption of electricity in Shrawan =2700-2500=200

Minimumcharge for first 50 units =Rs.299

Now, remaining units =200-50=150

Charges of remaining units =150×Rs.7.30 = RS 1095

∴Total charge =Rs. 299 + Rs 1095

= Rs. 1394. Ans.

  • Here,

By the rule of electricity authority, charges for up to 40 units is Rs.160 and charge for per additional unit is Rs 5.Here 225 units of electricity was consumed.

or, 224 units =40 units + 185 units

Here, charge for first 40 units = Rs.160 and charge for 185 units

185× 5=Rs 925.

Hence, the house owner should pay to electricity authority

Rs(160+925)=Rs.1085 Ans

  • Here, House owner uses only 40 units of electricity out of total 225 units each month and collect the charge of remaining (225-40)=185 units from the person living in rent.

∴ He receives for 185 units at the rate of Rs.6 per unit from the person living in rent.

∴ Total charge received from the person living in rent = Rs 6 × 185

= Rs.1110 Ans.

  • Here, House of the owner pays the charge Rs. 160 for up to 40 units.

Again, he pays for additional 185 units at the rate of Rs.5 per unit to the electricity authority.

∴ Charge for 185 units = 185× Rs.5=Rs. 925

Total charge to be paid =Rs.160 + Rs 925=Rs.1085

Charge for 185 units received from the person living in rent=Rs.1110

∴Profit made by the house owner =Rs.1110-Rs.1085

= Rs.25 Ans.

  • Here, The house owner consumed 60 units by himself and remaining 225-60=165 units are consumed by the person living in rent.

According to above (i) total amount of bill to be paid by the house owner to the electricity authority is Rs.1085

To consume 60 units free of cost bt house owner, he has to receive Rs. 1085 from 165 units.

Here, S.P of 165 = Rs.1085

∴S.P of 1 unit =\(\frac{Rs. 1085}{165}\)

= Rs.6.58.Ans.

Here,60 watt=\(\frac{60}{1000}\) kw=0.06 kw

7hrs.30 min = 7 hrs + \(\frac{30}{60}\)hrs

=7 \(\frac{1}{2}\)


Hence, total consumed units in 7 hrs.30 mins =0.06 ×\(\frac{15}{2}\)= 0.45 units.

Now, charge for 0.45 units at the rate of Rs.7.30 per unit =0.45× 7.30=Rs 3.285

∴Total charge to be paid for using a bulb of 60 w of 7 hours 30 minutes =Rs 3.285 Ans.

Again,2000w=\(\frac{2000}{1000}\)=2 kw

2 hours 15 minutes =2 hrs +\(\frac{15}{60}\)hrs.=2 hrs + 0.25 hrs =2.25 hrs.

Total consumed units from 2000 of heater = 2.25× 2 =4.5 units.

Now, Daily charges for 4.5 units at the rate of Rs.7.30

=Rs.(4.5× 7.30)

= Rs.32.85

Now, Daily charge for 1 month = 32.85× 30=985.5.Ans.

Here, Consumption of electricity in Baisakh = 1250-1050=200 units

Charge for first 100 units =Rs.664

Remaining units=200-100=100

Charge for remaining units=100 × Rs. 7.35 =Rs.735

Total charge = Rs.664 + Rs.735 =Rs.1399

  • First 100 units can be consumed for Rs.644.

Now, remaining amount =Rs.1058 - Rs Rs.644=Rs.394

Here,for Rs. 7.35 = 1 unit can be consumed

for Rs.1 = \(\frac{1}{7.35}\) unit can be consumed.

for Rs.394=\(\frac{1}{7.35}\)×394 unit can be consumed.

=53.6 units can be consumed.

∴Total units that can be consumed for Rs.1058

= 100 + 53.6 = 153.6 Units Ans.

Here, Initial charge for meter taxi = Rs.7

Total fare = Rs.115

Taxi fare for distance travelled=Rs.115 -Rs.7 =Rs. 108

Again,per km fare= Rs.9

Hence, total distance travelled =\(\frac{Rs.108}{Rs.9}\)=12 km

Hence, a passenger can travel 12 km for Rs.115.Ans.

Here, Initial charge for meter taxi = Rs.7

Total fare = Rs.115

Taxi fare for distance travelled=Rs.115 -Rs.7 =Rs. 108

Again,per km fare= Rs.9

Hence, total distance travelled =\(\frac{Rs.108}{Rs.9}\)=12 km

Hence, a passenger can travel 12 km for Rs.115.Ans.

Here, N.C 6.34 = 10 Japanese Yen

N.C =\(\frac{10}{6.34}\) Ja panese Yen

∴N.C. 22484.81=\(\frac{10}{6.34}\)×22484.81=35465 Japanese Yen Ans.

Here, from the given table,

I.C. 100 = N.C. 160

or,I.C.1 = N.C. \(\frac{160}{100}\)

or, I.C 25=N.C.\(\frac{160}{100}\)×25= N.C.40

Again, $ 1= N.C.Rs 78

∴ $ 6.82=N.C 78 × 6.82 =N.C.531.96

£ 1 = N.C.121.41

£ 3.9 =N.C. 121.41× 3.9 = N.C. 473.499

Hence, average fare of these three countries in Nepali currency


Rs.348.48 Ans.

Here, Air ticket from Ktm-London-Ktm=Rs 70225

Air ticket from London-Ktm-London =£ 604 =Rs. 604× 121.41

= Rs 73331.64

In Nepal, the air ticket is cheaper by

Rs. 7331.64 - Rs.70225 =Rs.3106

In percent, the ticket in Nepal is cheaper by



=4.42% Ans.

Here, C.P $ 1= Rs.78, S.P =£ 1=Rs.121.41

Actual profit =S.P -C.P=Rs.(121.41-78)

= Rs.43.41

Percentage of profit= \(\frac{Actualprofit}{C.P}\) × 100%

=\(\frac{43.41}{78}\)× 100%

=55.65% Ans.

Here, using chain rule,

Japanese Yen 10 =N.C.6.28

N.C. 35800=Japanese Yen x(say)

Here,10× 35800 = 6.28× x

∴ x=\(\frac{10× 35800}{6.28}\)

= 57006.37

Hence, N.C. 35800=Japanese Yen 57006.37 Ans.

Here, Let,£

Let,£ x can be exchange for Rs. 31200


Rs.390 = $ 5


Now, using chain rule,

x× 390× 20 =31200× 5× 15

∴ x= \(\frac{31200×5×15}{390× 20}\)

= 300

Hence, number of pounds that can be exchanged forRs.31200 is£300.Ans.


Let, $ 55 =£x


$1 =Rs.78

Rs.117 =£1

Now, x×1×117 =55× 78× 1



∴$55=£36.67 Ans.

Here, Rs. 78.59 = $1


or, Rs. 70250 =$\(\frac{1}{78.59}\)×70250

= $ 893.88 Ans.


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