Question

Gabby and Sydney bought some pens and pencils. Gabby bought 4 pens and 5 pencils for $6.71. Sydney bought 5 pens and 3 pencils for $7.12.

Answer 1

Explanation:

x = pens and y = pencils

4x + 5y = 6.71....multiply by 5

5x + 3y = 7.12....multiply by -4

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

20x + 25y = 33.55 (result of multiplying by 5)

-20x - 12y = - 28.48 (result of multiplying by -4)

--------------------add

13y = 5.07

y = 5.07 / 13

y = 0.39 <=== cost of a pencil

4x + 5y = 6.71

4x + 5(0.39) = 6.71

4x + 1.95 = 6.71

4x = 6.71 - 1.95

4x = 4.76

x = 4.76/4

x = 1.19 <==== cost of a pen