Question:The population of a town is 176400. If it increases at the rate of 5% per annum, what will be its population 2 years hence ?
What was it 2 years ago ? 

Population after 2 years

 = `176400 xx (1 +5/100)^2`

 = `(176400 xx 21/20 xx 21/20)` 

 = 194481.

 Population 2 years ago 

 = `176400/(1 +5/100)^2` 

 = `(176400 xx 20/21 xx 20/21)`

 = 160000.

Question:The value of a machine depreciates at the rate of 10% per annum. If its present value is Tk. 162000,What will be its worth after 2 years ?What was the value of the machine 2 years ago ? 

Value of the machine after 2 years  

 = `Tk. [162000 xx (1 -10/100)^2]`

 = `Tk.(162000 xx 9/10 xx 9/10)` 

 = Tk. 131220.

 Value of the machine 2 years ago 

 = `Tk.{162000/(1 -10/100)^2}` 

 = `Tk (162000 xx 10/9 xx 10/9)` 

 = Tk. 200000.

Question:A man buys an article for tk 27.50 and sells it for tk 28.60. find his gain percent. 

4%

Question:If a ratio is purchased for tk 27.50 and sells it for tk 28.60. Find his gain percent. 

C.P = Tk 450

 S.P = Tk 465.50

 Loss =Tk`(490-465.50)` 

 = Tk 24.50

 :. Loss % = `((24.50)/490xx 100)` %

  = 5%

Question:By selling a book for tk 115.20, a man loses 10%. At what price should he sell it to gain 5%? 

Let the new S.P be Tk x

 (100-Loss%) : (1st S.P) = (100 + gain%): (2nd S.P)

 or, `(100-10)/115.20` = `(100+5)/x`

 or, x = `(105 xx 115.20/90)` = 134.40 

 `:.` New S.P = Tk 134.40

Question:A trader lost 20% by selling  a watch for tk 1024. What percent shall he gain or loss by selling it for tk 1472? 

Let the new gain be  x%

Then, 80 : 1024 = (100 + x) : 1472

or, `80/1024` = `(100+x)/1472`

or, 100 + x = `(80 xx 1472)/1024` = 115

So, x = 15%

Question:Ashok purchased a radio set and sold it to Shayam at a profit of 25 % and shayam sold it to Mohan at a loss of 10 % and Mohan paid tk 675 for it. For how much did Ashok purchased it? 

Suppose Ashok purchased it for tk x

 Then, 90 % of x = 675

 :.`90/100 xx 125/100 xx x` = 675

 or, `(675 xx 100/125 xx 100/90)` = 600 tk

Question:A man sold two houses for tk 675958 each. On one he gains 16 % while on the other he loses 16 %. How much does he gain or loss in the whole transaction? 

2.56 %

Question:The orginal price of a T.V set is Tk 9000 the price is discounted by 20 % then raised by 10 % what is its new price? 

Tk 7920

Question:The C.P of 12 articles is equal to S.P of S.P of 9 articles. Find the gain percent : 

` 33 1/3` %