Question

The cost of five pencils and one pen is 2.50$, and the cost of one pencil and two pens is 1.85$. What is the cost of two pencils and one pen?

Answer 1

5.50

Explanation:

make two equations:
`x + y = 2.50`

and
`2x + 3y = 5.50`

we can multiply the top equation by -2

-2x - 2y = 5.00

2x + 3y = 5.50

+

---------------------

`y = .50`

We can plug y into the first to get
`x + .50 = 2.50`

add them up to get 5.50

Hope this helps :)

Answer 2

Let pc be pencils, and pn be pens. Then:
5pc+pn=250
pc+2pn=185
Then
10pc+2pn=500
pc+2pn=185
9pc=315
pc=35
pn=75
Pencils are 35 cents; pens are 75 cents