Question

a pen cost rupee 2x and notebook cost rupee 3y find the total cost of 3 pens and 4 notebook​

Answer 1

Let the price of 1 pen =Rs. X

Let the price of 1 notebook = Rs. Y

Hence 2x +3y= 40 - (1)

And 2x + 6 y = 60 - (2)

Subtract eq (1) from eq (2 )

Then 3y = 20

Hence y = 20/3 Rs.

Put the value of y in eq (1)

Then 2x + 3×(20/3) =40

2x +20 = 40

2x = 20

x = 10 Rs

Hence the price of 1 pen is 10 Rs. and the price of 1 notebook is 20/ 3 Rs.

Answer 2

Let the price of 1 pen =Rs. X

Let the price of 1 notebook = Rs. Y

Hence 2x +3y= 40 - (1)

And 2x + 6 y = 60 - (2)

Subtract eq (1) from eq (2 )

Then 3y = 20

Hence y = 20/3 Rs.

Put the value of y in eq (1)

Then 2x + 3×(20/3) =40

2x +20 = 40

2x = 20

x = 10 Rs