social arithmetic
DESCRIPTION
TRANSCRIPT
Chapter 4 – Mathematics 7
BPK Penabur GSBy : Mr . Ronald Naradus S
*SOCIAL ARITHMETIC
GLOSSARY
• Cost, Buying price = harga pembelian , biaya• Selling price = harga penjualan• Profit, gain = laba/untung• Loss = rugi• Marked price, original price = harga kotor, harga sebelum didiskon• Discount = potongan harga, rabat, diskon• Sale price, cheaper price = harga bersih, harga setelah didiskon• interest = bunga• interest rate = suku bunga• Simple interest = bunga tunggal• Compound interest = bunga majemuk• Bruto = Berat kotor• Netto = berat bersih• Tarra = Berat bungkus• Principal = Modal mula-mula
Profit and Loss
Selling price > Buying price (cost)
Buying price (Cost ) > Selling price
Profit / Gain
Loss
PROFIT ( Selling Price > Buying Price )
• Profit = Selling Price – Buying Price (Cost)• Buying Price = Selling Price – Profit• Selling Price = Buying Price + Profit
• Loss = Buying Price – Selling Price • Selling Price = Buying Price – Loss• Buying Price = Selling Price + Loss
LOSS ( Buying Price > Selling Price )
Example 1 ! Pg 43 no 1Copy this table into your book and fill the blank!
Buying Price Profit/ Loss / Equal Selling Price
Rp 25.000 Profit Rp 3500
Rp 14.000 Loss Rp 1750
Profit Rp 2250 Rp 34.500
Rp 34.500 Rp 35.400
Loss Rp.2250 Rp 25.250
Rp 17.500 Rp 16.250
Rp 28500
Rp 12250
Rp 32250 Profit Rp
900Rp
27500 Loss Rp 1250
Example 2 ! Pg 43 no 5 A fruit seller buys
650 oranges for Rp 78000. he sells 400 oranges at Rp 200 each and 200 oranges at Rp 150 each. If the rest are not sale because they are rotten, calculate the profit or loss!
Answer Buying price : Rp 78000Selling price :(400 x Rp 200 ) + ( 200 x Rp 150 ) Rp 80000 + Rp 30000 Rp 110000
Profit = Selling price – Buying price
= Rp 110000 – Rp 78000
= Rp 32000
Example 3! Page 43 no 2Adi bought a second hand bicycle for Rp 72000. After he repaired, he sold the bicycle.a) If the repairing cost is Rp. 24000, how much did Adi sell it to get Rp
15000 profit b) If Adi sold it for Rp 85000 and He got Rp 7500 loss How much did the repairing cost?
ANSWERa) Buying price : Rp 72000 Repairing Cost : Rp 24000 Profit : Rp 15000 Selling price ?
Selling Price = Buying Price + ProfitSelling Price = ( Buying price + Repairing cost ) + ProfitSelling Price = (Rp 72000 + Rp 24000 ) + Rp 15000Selling price = Rp 96000 + Rp 15000
Selling Price = Rp 111000
ANSWERb) Buying price : Rp 72000 Selling Price : Rp 85000 Loss : Rp 7500 Repairing Cost ?
Buying Price = Selling Price + Loss( Buying price + Repairing cost ) = Selling Price + Loss(Rp 72000 + Repairing Cost ) = Rp 85000 + Rp 7500Repairing Cost = Rp92500 - Rp 72000
Repairing Cost = Rp 20500
Do Exercise 28 page 43 no 2, 3, 4
Percentage profit & Percentage loss
Example ! Pg 44 no 1
Goods bought for Rp 72.000 and sold at Rp 90.000Find the percentage profit of the cost price !
Solution!Profit = Rp 90.000 – Rp 72.000
= Rp 18.000
% Profit = = 25%
*Smart Solution☺
If given, buying price and percentage of profit :
if given, buying price and percentage of loss :
Smart Solution☺ If given, selling price and percentage of profit :
if given, selling price and percentage of loss :
Example !
Arman buys a secondhand bicycle for Rp 350.000. Find the selling price, if Arman sold at a profit of 12 %!
DO EXERCISE 29 PAGE 44 NO 2, 3
Bruto, Netto and Tarra Bruto : the total weight ( the content and
the package ) Netto : the net weight ( only the content ) Tarra : the weight of package
In mathematics, we can write :
Bruto = Netto + TarraNetto = Bruto – Tarra Tarra = Bruto - Netto
Bruto / Total Weight Netto/ Net Weight Tarra
100kg 98,5 kg
50 kg 0,5 kg
33,7 kg 1,3 kg
Example 1 ! Pg 44 no 5
Bruto = Netto + TarraNetto = Bruto – Tarra Tarra = Bruto - Netto
1,5 kg49,5 kg
35 kg
Example 2 ! Pg 44 no 6 A retailer buys one
bag of cane sugar for Rp 120000. In bags are written : Total weight 100 kg Net weight 98 kg. This cane sugar sold for Rp 1400/ kg and ex-sugar bag sold for Rp 1500. How much will the store get profit from selling one bag?
Known : Buying price : Rp 120000Selling price :(98 kg x Rp 1400 ) + ex- sugar bagRp 137200 + Rp 1500Rp138700
Profit = Selling price – Buying price
= Rp 138700 – 120000
= Rp 18700
Discount / Rebate
• Discount also call rebate
• Rebate is usually used to
attract people’s interest.
• Rebate is usually express in percent (%).
Discount = marked price - sale price
Example ! At Kompas yesterday, there’s an
advertisement said that Gramedia at Grand Indonesia will give 30% discount for the BCA card holders. So, Ucup goes there to buy some books. If he buys 5 books for Rp. 150.000,00 and he pays with BCA cards, how much does he pay ? Actual Price = Rp. 150.000,00
Discount ( 30% x Rp. 150.000,00 ) = Rp. 45.000,00 -
Price after discount = Rp. 105.000,00
Principal - Interest
Types of Interest
interest which is calculated onthe original principal
Simple interest
interest which is calculated onthe amount of money at the endof each interest period(including interest)
Compound interest
Interest rate
Yearly or annually (per year or per annum)Semi annually or half-yearly (per a half year)Quarterly (per a quarter year or per 3 months)Monthly (per month)Weekly (per week)Daily (per day)
I R P
Total P I
Principal = Modal, Invest
Simple Interest ( Yearly )
Simple Interest ( Monthly )Where :I = Simple InterestP = PrincipalR = Interest Rate ( in %)t = time
Principal = Modal, Invest
Pardi invested his money in a bank Rp 15.000.000At rate of 18% per-annum. Calculate the simple interest Pardi received :a. at the end 1 yearb. at the end of 2 yearsc. After 7 yearsd. At the end of 8 months
Example 1! Pg 46 no 1
Given : Principal = Rp 15.000.000
Rate = 18% = 0, 18a) t = 1 year
I = P . R .tI = 15.000.000 x 0,18 x 1I = 2.700.000
So, Pardi received the simple interest for 1 year is Rp 2.700.000
Solution
Given : Principal = Rp 15.000.000Rate = 18% = 0,18
b. t = 2 yearsI = Rp 2.700.000 x 2I = Rp 5.400.000
c. t = 7 yearsI = Rp 2.700.000 x 7 I = Rp 18.900.000
d. t = 8 months
I = Rp 1.800.000
Principal( P )
Rate( R )
Time( t )
Simple Interest
( I )
The amount
at the end
200.000 5% Per-annum
2 years
1.500.000 2%Half yearly
One-half year
2 ½ % monthly
7 months 52.500
8%Per-annum
11 months 2.250.000
600.000 1 year 5 months
127.500
Copy this table into your book and fill the blank!
20.000 220.000
90.000 1.590.000
44.680,85 7819,15
2.096.273,29 153.726,71
15 %Per- annum 727.500
DO EXERCISE 30 PAGE 46 NO 1 - 4
GOD BLESS YOU ☺
Thank You For Your Attention