Patrick brought notebook and pens for her daughters, he brought 8 notebooks and 3 pens for isha and spent 365pesos .for any he brought 3 notebooks and 2 pens

Question

Patrick brought notebook and pens for her daughters, he brought 8 notebooks and 3 pens for isha and spent 365pesos .for any he brought 3 notebooks and 2 pens and spent 150 pesos.How much the notebook and pen?

Notebook=
Pen=

Answer 1

N = price of notebook
P = price of the pen


8N + 3P = 365
3N + 2P = 150


Need to multiply both equations by compatible numbers so
one of the unknowns drops out when you add them together.
For example:
Multiplies the top equation by 2 and the bottom equation by -3


16N + 6P = 730
-9N + -6P = -450


Adds them together, the P drops out!


7N = 280
N = 40
So the notebook costs 40 pesos.


Now uses the original second equation to
find the price of the pen because the numbers are smaller.


3 x 40 + 2P = 150
120 + 2P = 150
2P = 30
P = 15
so the price of the pen is 15 pesos.


CHeck: using the original first equation,
8 notebooks and 3 pens costs
8 x 40 + 3 x 15 = 320 + 45 = 365 pesos.