Question

Jose bought 3 pens and 6 pencils for $6.60. Amy bought 5 pens and 8 pencils for $10.00. How much does one pencil cost?

Appreciate it :)

Answer 1

pen = $1.20, pencil = $0.50

Explanation:

let x = pen

let y = pencil

create system of equations:

3x + 6y = 6.60 [can be simplified to be x + 2y = 2.20]

5x + 8y = 10.00

substitution method:

x = 2.2 - 2y

5(2.2 - 2y) + 8y = 10

11 - 10y + 8y = 10

-2y = -1

y = 1/2

solve for 'x':

3x + 6(1/2) = 6.6

3x + 3 = 6.6

3x = 3.6

x = 1.2