Question 329272
Let S be the number of silk ties, N the number of non-silk ties.
1.{{{S+N=17}}}
2.{{{3.60S+3.25N=58.75}}}
From eq. 1,
{{{S=17-N}}}
Subsitute into eq. 2,
{{{3.6(17-N)+3.25N=58.75}}}
{{{61.2-3.6N+3.25N=58.75}}}
{{{-0.35N=-2.45}}}
{{{highlight(N=7)}}}
From eq. 1,
{{{S+7=10}}}
{{{highlight(S=10)}}}