Question

the total cost of 6 books and 7 pens is 79 rupees and the cost of 7 books and pipe is 77 rupees find the cost of one book and two points

Answer 1

Let the cost of the book be x

And the cost of pen be y

Then the cost of 6 books n 7 pens is

6x+7y = 79

And 7x+6y = 77

Now let us add both equations

13x + 13y = 156

X+y = 12

Let us subtract both equations

-x + y = 2

Now let us add the equations so obtained then

X-x + y +y = 12 + 2

2y = 14

y = 7

Substitute in one equation then

X + 7 = 12

X = 5

So the cost of one book is 5

And one pen is 7

So the cost of 1 book and 2 pens is

X + 2y = 5 + 2(7) = 5 + 14 = 19

HEY MATE PLEASE MARK ME AS A BRAINLIST ANSWER AND FOLLOW ME

Answer 2

Let the cost of the book be x

And the cost of pen be y

Then the cost of 6 books n 7 pens is

6x+7y = 79

And 7x+6y = 77

Now let us add both equations

13x + 13y = 156

X+y = 12

Let us subtract both equations

-x + y = 2

Now let us add the equations so obtained then

X-x + y +y = 12 + 2

2y = 14

y = 7

Substitute in one equation then

X + 7 = 12

X = 5

So the cost of one book is 5

And one pen is 7

So the cost of 1 book and 2 pens is

X + 2y = 5 + 2(7) = 5 + 14 = 19