Question

Samuel spent $16 for 4 erasers and 2 pencils. Alva spent $10.50 for 3 erasers and 1 pencil. How much does 5 erasers and 3 pencils cost?

$___.00

Answer 1

Explanation:

Let E = Erasers and P = Pencils

4E + 2 P = $16…(1)

3E + 1P = $10.50…(2)

Multiply (2) by 2 to make Pencils in (1) and (2) equal.

6E + 2P = $21…(3)

Subtract (3) from (1) to eliminate P

2E = $5 => Erasers = $2.50 each

Substitute this value for Erasers into (3)

6 * $2.50 + 2P = $21

2P = $21 - $15 = $6 => Pencils = $3

Therefore 5 Erasers + 3 Pencils cost

5 * $2.50 + 3 * $3 = $12.50 + $9 = $21.50