1. *
Chapter 4 – Mathematics 7
BPK Penabur GS
By : Mr . Ronald Naradus S
2.
3. • 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
GLOSSARY
4. Selling price > Buying Profit
price (cost) / Gain
Buying price (Cost ) >
Selling price
Loss
Profit and Loss
6. Example 1 ! Pg 43 no 1
Copy this table into your book and fill the blank!
Buying Price Profit/ Loss / Equal Selling Price
Rp 25.000 Profit Rp 3500
Rp 28500
Rp 14.000 Loss Rp 1750
Rp 12250
Profit Rp 2250 Rp 34.500
Rp 32250
Rp 34.500 Rp 35.400
Profit Rp 900
Loss Rp.2250 Rp 25.250
Rp 27500
Rp 17.500 Rp 16.250
Loss Rp 1250
7. Example 2 ! Pg 43 no 5
A fruit seller buys 650 Answer
oranges for Rp 78000. Buying price : Rp 78000
he sells 400 oranges Selling price :
at Rp 200 each and
(400 x Rp 200 ) + ( 200 x Rp 150
200 oranges at Rp
)
150 each. If the rest
are not sale because Rp 80000 + Rp 30000
they are rotten, Rp 110000
calculate the profit or
loss! Profit = Selling price – Buying
price
= Rp 110000 – Rp 78000
= Rp 32000
8. Example 3! Page 43 no 2
Adi 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?
9. ANSWER
a) Buying price : Rp 72000
Repairing Cost : Rp 24000
Profit : Rp 15000
Selling price ?
Selling Price = Buying Price + Profit
Selling Price = ( Buying price + Repairing cost ) +
Profit
Selling Price = (Rp 72000 + Rp 24000 ) + Rp
15000
Selling price = Rp 96000 + Rp 15000
Selling Price = Rp 111000
10. ANSWER
b) 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 7500
Repairing Cost = Rp92500 - Rp 72000
Repairing Cost = Rp 20500
18. 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 + Tarra
Netto = Bruto – Tarra
Tarra = Bruto - Netto
19. Example 1 ! Pg 44 no 5
Bruto / Total Weight Netto/ Net Weight Tarra
100kg 98,5 kg
1,5 kg
50 kg 49,5 kg 0,5 kg
35 kg 33,7 kg 1,3 kg
Bruto = Netto + Tarra
Netto = Bruto – Tarra
Tarra = Bruto - Netto
20. Example 2 ! Pg 44 no 6
A retailer buys one Known :
bag of cane sugar for Buying price : Rp 120000
Rp 120000. Selling price :
In bags are written :
Total weight 100 kg (98 kg x Rp 1400 ) + ex- sugar
Net weight 98 kg. bag
This cane sugar sold Rp 137200 + Rp 1500
for Rp 1400/ kg and Rp138700
ex-sugar bag sold for
Rp 1500. How much
Profit = Selling price – Buying
will the store get profit
price
from selling one bag?
= Rp 138700 – 120000
= Rp 18700
21. • Discount also call rebate
• Rebate is usually used to
attract people’s interest.
• Rebate is usually express
in percent (%).
Discount = marked price - sale price
Discount / Rebate
22. 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
24. Types of Interest
Simple interest
Compound interest
interest which is
calculated on interest which is calculated on
the amount of money at the
the original principal end
of each interest period
(including interest)
25. 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)
Interest rate
26. Simple Interest ( Yearly )
Principal =
Modal, Invest
I R P
Total P I
27. Simple Interest ( Monthly )
Where :
I = Simple Interest
P = Principal
R = Interest Rate ( in %)
t = time
Principal =
Modal, Invest
28. Example 1! Pg 46 no 1
Pardi invested his money in a bank Rp 15.000.000
At rate of 18% per-annum. Calculate the simple interest
Pardi received :
a. at the end 1 year
b. at the end of 2 years
c. After 7 years
d. At the end of 8 months
29. Solution
Given : Principal = Rp 15.000.000
Rate = 18% = 0, 18
a) t = 1 year
I = P . R .t
I = 15.000.000 x 0,18 x 1
I = 2.700.000
So, Pardi received the simple interest for 1 year is Rp 2.700.000
30. Given : Principal = Rp 15.000.000
Rate = 18% = 0,18
b. t = 2 years
I = Rp 2.700.000 x 2
I = Rp 5.400.000
c. t = 7 years
I = Rp 2.700.000 x 7
I = Rp 18.900.000
31. Copy this table into your book and fill the blank!
Principal Rate Time Simple Interest The amount
(P) (R) (t) (I) at the end
200.000 5% 2 years
Per-annum
1.500.000 2% One-half year
Half yearly
2½ % 7 months 52.500
monthly
8% 11 months 2.250.000
Per-annum
600.000 1 year 127.500
5 months
