We are given
Staples sells pencils in packs of 12 pencils for 3.50
so, staples cost is
[tex] =\frac{3.50}{12} [/tex] per pencil
[tex] =0.29167 [/tex] per pencil
Office max sells pencils in packs of 15 pencils for 6.50
so, office max cost is
[tex] =\frac{6.50}{15} [/tex] per pencil
[tex] =0.4333 [/tex] per pencil
now, we can find their differences
[tex] =0.4333-0.29167 [/tex] per pencil
[tex] =0.14 [/tex] per pencil............Answer