Question

In a stationary store,pencils have one price and pens have another price.Two pencils and three pens cost 78 cents.However, 3 pencils and 2 pens cost 72 cents . How much does one pencil cost?

Answer 1

Answer:

Pencils cost $0.12

Step-by-step explanation:

Set up a system of equations :D

let x represent pencils

let y represent pens

2x + 3y = 0.78

3x + 2y = 0.72

Because we are only interested in pencils we will solve for x first.

Isolate y in either equation, lets do the first one.

3y = 0.78 - 2x

y = (0.78 - 2x)/3

Simplify

y = 0.26 - (2x/3)

Now plug what we got into Y in the other equation

3x + 2 (0.26 - (2x/3)) = 0.72

solve by simplifying

3x + 0.52 - (4x/3) = 0.72

3x - (4x/3) = 0.20

9x/3  -  4x/3 = 0.20

lets change 0.2 into a fraction 2/10 simplified to 1/5

5x/3 = 1/5

25x/15 = 3/15

25x=3

x= 3/25 = 0.12