Math, asked by IamRahul4994, 1 year ago

shalini purchased compass box and pen for rs 40 .if she had paid rs 5 more to buy compass box and paid 3 less to pen the product of their cost would be rs 360 find the cost of compass box and pen

Answers

Answered by knjroopa
7

Answer:


Step-by-step explanation:

Given Shalini purchased compass box and pen for rs 40 .if she had paid rs 5 more to buy compass box and paid 3 less to pen the product of their cost would be rs 360 find the cost of compass box and pen

Let the compass box be x and pen be y. According to the question

 x + y = 40 and (x + 5)(y - 3) = 360

  y = 40 - x

So taking (x + 5)(y - 3) = 360

               (x + 5)(40 - x - 3) = 360

                (x + 5)(37 - x) = 360

               37 x + 185 - x^2 - 5 x = 360

              - x^2 + 32 x - 175 = 360

               x^2 - 32 x + 175 = 0

             x^2 - 25 x - 7 x + 175 =0

            x(x - 25) - 7(x - 25) = 0

             (x - 25)(x - 7) = 0

           x - 25 = 0 and x - 7 = 0

         x = 25, 7

 So y = 40 - x

     y = 40 - 25 or y = 40 - 7

     y = 15, 33

 The cost of compass box is rs 25  and pen is rs 15

Answered by lodhiyal16
4

Answer:


Step-by-step explanation:

Shalini purchased compass box and pen for rs. 40

Let be the compass be x and pen be y

X + Y = 40

Y = 40 -X .....(1)

If she paid 5 more to buy compass box = (X+5)

She paid less 3 to buy pen = (y-3)

And their produt is 360

So,

(x+5) (y-3) = 360

Putting the value of y in this equation

(x+5) (40-x -3)= 360

(x+5) (37-x) = 360

37x -x²+ 185 -5x + 360

32x - x² = 360 - 185

32x - x ²= 175

32x - x² -175 = 0

x² - 32x + 175 = 0

x² - 25x - 7x + 175 = 0

x(x-25)- 7(x-25 ) = 0

x-25 =0, x-7 = 0

x = 25 ,7

So y = 40 - x

y = 40 - 25   or y = 40-7

y= 15  or y= 33

So we take 25 , 15 because their sum is 40

Cost of compass be 25 and pen is 15.



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