Question

5 pens and 7 pencil cost ruppes 50 and 7 pen and 5 pencil cost rupees 46 what is the cost of 2 pen and 3pencil
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Answer 1

To Find :

• Cost of 2 pens and 3 pencils

Solution :

Let the cost of pen be x and cost of pencil be y.

$\large\underline{ \underline \red{ \boldsymbol{ \dag \: \mathscr{A}ccording \: To \: \mathscr{Q}uestion : - }}}$

Cost of 5 pens and 7 pencils is Rs 50

5x + 7y = 50 ....1)

Cost of 7 pen and 5 pencils is Rs 46

7x + 5y = 46 ........2)

• Multiplying equation (1) by 7 and (2) by 5

(5x + 7y = 50) × 7

And , (7x + 5y = 46) × 5

We get,

35x + 49y = 350 .....3)

35x + 25y = 230 ......4)

Solving Equations (3) and (4) By Elimination method.

⠀⠀⠀⠀⠀35x + 49y = 350

⠀⠀⠀⠀⠀35x + 25y = 230

⠀⠀⠀⠀ ⠀--⠀⠀⠀--⠀⠀⠀ --⠀⠀

⠀⠀⠀⠀⠀⠀⠀⠀⠀24y = 120

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀y = 120/24

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀y = 5

• Substituting value of y in eq. (1)

5x + 7y = 50

5x + 7× 5 = 50

5x + 35 = 50

5x = 50 - 35

x = 15/5

• x = 3

So,

• Cost of 2 pen 2x

= 2 × 3

= Rs 6

• Cost of 3 pencils 3y

= 3 × 5

= Rs 15

$\underline{ \underline \red{ \boldsymbol{ \dag \:Hence }}}$

$\green{\textrm{Cost of 2 pens and 3 pencils is Rs 6, and Rs 15}}$

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