Math, asked by maahiparekh05, 7 months ago

Amrita bought some pens for Rs 360. When the price was reduced by Rs 3, she could buy 6 more pens for the same cost of Rs360. Find the original cost of the pen​

Answers

Answered by Anonymous
4

Answer:

Step-by-step explanation:

let,no of pen is x

and cost of pen is y

from the first condation

xy=360

from the sec cond

(y-3)(6+x)=360

y(6+x)-3(6+x)=360

6y +xy-18-3x =360

put xy=360

6y+360-18-3x=360

6y+ 342-3x=360

-3x+6y=18 take 3 common

-x+y=6

put x=360/y

-360/y+y=6

y=6y/360

Answered by shravanigondhalekar2
13

Answer:

no. of pens she bought = x

Rs. = 360

Cost 1 = 360/x

No. of pens she could have bought = x + 6

Rs. = 360

Cost 2 = 360/( x + 6 )

C 1 is greater than C 2 by 3

C1 = C2+3

 \frac{360}{x}  =  \frac{360}{x + 6}  + 3

 \frac{360}{x}  -  \frac{360}{x + 6 }  = 3

360( \frac{1}{x}   -  \frac{1}{x + 6} ) = 3

360( \frac{x + 6 - x}{ {x}^{2} + 6x })  = 3

 \frac{360 \times 6}{ {x}^{2}  + 6x}  = 3

2160 = 3 {x}^{2}  + 18x

3 {x}^{2}  + 18x - 2160 = 0

 {x}^{2}  + 6x - 720 = 0

 {x}^{2}  + 30x - 24x - 720 = 0

x(x + 30) - 24(x + 30) = 0

(x + 30)(x - 24) = 0

x = -30 x = 24

No. of pens she bought is 24.

Cost = 360/24

= 60/4

= 15 rs.

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