Question

At the school store, 3 pens and 2 notebooks cost a total of $12, while 1 pen and 3 notebooks cost a total of $11. This can be represented by the system of equations, where x stands for the cost, in dollars, of pens, and y stands for the cost, in dollars, of notebooks.

What is the cost of one notebook?
A.$2.40
B.$2.75
C.$2.00
D.$3.00

Answer 1

One notebook is $3.00

Explanation:

3x + 2y = $12

1x + 3y = $11

Add -3y to the second equation

x = 11 - 3y

Substitute ( 11 - 3y ) for x in 3x + 2y = 12

3 ( 11 - 3y ) + 2y = 12

33 - 9y + 2y = 12

33 - 7y = 12

Add -33 to each side

-7y = -21

Divide each side by -7

y = 3

substitute 3 for y in x = 11 - 3y

x = 11 - 3(3)

x = 11 -9

x = 2

One notebook is $3.00

Answer 2

D

Explanation:

the reason why is because if you put 3 dollars in for the notebooks right you have 3x3=9 and that one pen will be 2 dollars. Now you have 3×2=6 and then the two notebooks will be 6 and you add that and get 12. Hope this helps