Again, if cost price is Tk. 100, selling price at the profit of s% is Tk. ( 100 s)

? ,, ,, ,, ,, Tk. 1 ,, ,, ,, ,, ,, ,, ,, ,, Tk.
100

100 s

? ,, ,, ,, ,, Tk.
100 r

100

,, ,, ,, ,, ,, ,, ,, Tk. ̧

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·

̈

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§



u



r

s

100

100

100

100

= Tk.
r

s





100

100

? in Tk.
r

s





100

100

, number of oranges is to be sold = n

? in Tk. 1, ,, ,, ,, ,, ,, ,, ,, ̧
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·

̈

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§





u

s

r

n

100

100

Hence,
s

n r





100

( 100 ) oranges are to be sold per taka.

Example 7. What is the profit of Tk. 650 in 6 years at the rate of profit Tk. 7 percent
per annum?

Solution : We know , I Pnr.

Here,P Tk. 650, n 6 ,s 7

?
100

7

100

s

r

? 273
100

7

I 650 u 6 u

Hence, profit is Tk. 273.

Example 8. Find the compound principal and compound profit of Tk. 15000 in 3
years at the profit of 6 percent per annum.

Solution : We know, C P( 1 r)n, where C is the profit principal in the case of
compound profit.

Given, P Tk. 15000 ,
100

6

r 6 % ,n = 3 years

?

3 3

50

3

150001

100

6

(^150001) ̧
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̧
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C §

3
50
1500053
̧
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