A store sells pencils and erasers 4 pencils and 10 erasers cost 5.50 6 pencils and 5 erasers cost 5.75. How much would 8 pencils and 8 erasers cost?

Answer 1

4p + 10e = 5.5

6p + 5e = 5.75

I'm going to multiply the 2nd equation by -2.

-12p - 10e = -11.5

Adding that to the 1st...

-8p = -6

p = 0.75

4(0.75) + 10e = 5.5

3 + 10e = 5.5

10e = 2.5

e = 0.25

8(0.75 + 0.25) = $8