SOLUTION: a shop owner orders a number of drinking glasses which she pays R300, while unpacking the glasses, 10 get broken she decide to sell each remaining glasses at R4 more than she pai

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Question 1152383: a shop owner orders a number of drinking glasses which she pays R300, while unpacking the glasses, 10 get broken she decide to sell each remaining glasses at R4 more than she paid for them . she manages to make a profit of R100 on the transaction. how many glasses did she initially order and what was the price the price of each?
Answer by ikleyn(52808) About Me  (Show Source):
You can put this solution on YOUR website!
.

Let x be the value under the question (the original number of glasses).


Then the price for each glass when buying is  300%2Fx rupees.


She made R100 profit selling, so she sold for R300 + R100 = R400.


The number of glasses sold is (x-10), according to the condition.


For each of (x-10) glasses sold, she get R4 more than paid per glass buying.


It means that


    400%2F%28x-10%29 - 300%2Fx = 4.    (1)


It is your basic equation.


To solve it, multiply both sides by x*(x-10).  You will get


    400x - 300*(x-10) = 4x*(x-10).


Simplify step by step and solve


    400x - 300x + 3000 = 4x^2 - 40x

    4x^2 -40x - 100x - 3000 = 0

    4x^2 - 140x - 3000 = 0

     x^2 - 35x - 750 = 0

    (x-50)*(x+15) = 0  


Of the two roots, 50 and -15, only positive value x= 50 is the solution.


ANSWER.  50 glasses were bought at the price of  300%2F50 = R6.


CHECK.  I will check that the equation (1) is valid.


        400%2F%2850-10%29 - 300%2F50 = 400%2F40 - 300%2F50 = 10 - 6 = 4.    ! Precisely correct !

Solved.

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