Math, asked by felwinbenny, 4 months ago

The price of 3 notebooks and 4 pens is 65 rupees and the price of 4 notebooks and 5 pens is 85 rupees. Find the price of a notebook and the price of a pen? ​

Answers

Answered by sonu5264
0

Answer:

Let book, notebook, pen be x, y, z respectively.

2x+6y+3z=40

3x+4y+2z=35

5x+7y+4z=61

2

3

5

6

4

7

3

2

4

x

y

z

=

40

35

61

Apply R

1

→R

1

−R

2

−1

3

5

2

4

7

1

2

4

x

y

z

=

5

35

61

Now R

1

→(−R

1

)

1

3

5

−2

4

7

−1

2

4

x

y

z

=

−5

35

61

R

2

→R

2

−3R

1

& R

3

→R

3

−5R

1

1

0

0

−2

10

17

−1

5

9

x

y

z

=

−5

50

86

R

2

10

1

R

2

,

1

0

0

−2

1

17

−1

2

1

9

x

y

z

=

−5

5

86

R

3

−17R

2

,

1

0

0

−2

1

0

−1

2

1

2

1

x

y

z

=

−5

5

1

Now x−2y−z=5, y+

2

z

=5,

2

z

=1

⇒z=2,y=4,x=5.

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