Question

A watch sold 500 to 640 then profit earn more than 10%, what is the cost price of it?​

Answer 1

S.P of first article = Rs. 640

Profit =20%

Then C.P of the first article =

100+20

100

×640= Rs. 533.33

S.P of second article= Rs. 640

Profit =10%

Then C.P of the second article =

110

100

×640=581.81

Total S.Pc =640+640= Rs. 1280

Total C.P =533.33+581.81= Rs. 1115.14

S.P. > C.P.

Therefore, profit =1280−1115.14= Rs. 164.86

Profit % =

1115.14

164.86

×100=14.78%

Answer 2

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★ Explanation ★

Solution – It is given that the girl buys lemons at 4 for Rs 3 and sells them at 5 for Rs 4. Therefore, to avoid frictions assume that the girl buys and sales 4 times 5= 20 lemons.

We have,

C.P.of4lemons=Rs3/−C.P.of1lemon=Rs34/−C.P.of20lemons=Rs34×20=Rs15/−S.P.of5lemons=Rs4/−S.P.of1lemon=Rs45/−S.P.of20lemons=Rs45×20=Rs16/−

Clearly,  S.P.> C.P. It means girl makes Profit.

Profit=S.P.–C.P.Profit=Rs.16−Rs.15Profit=Rs.1/−

Hence, Gain in percentage

Profitpercent=(ProfitC.P.)×100

Profit%=(115)×100%

Profit%=203%