let
the price of shirt = x
the price of the pair of pants = y
a. An equation to represent the total amount Barney spent can be represented below
[tex]3x+2y=70[/tex]b. An equation to describe the total amount spent by Robin in terms of number of shirt and pants can be written below
[tex]x+4y=90[/tex]c. The equations formed can be solved below
[tex]\begin{gathered} 3x+2y=70 \\ x+4y=90 \\ x=90-4y \\ 3(90-4y)+2y=70 \\ 270-12y+2y=70 \\ 270-10y=70 \\ 270-70=10y \\ 200=10y \\ y=\frac{200}{10} \\ y=20 \\ \\ 3x+2y=70 \\ 3x+2(20)=70 \\ 3x+40=70 \\ 3x=70-40 \\ 3x=30 \\ x=\frac{30}{3} \\ x=10 \end{gathered}[/tex]d.
The co ordinates point where the two lines intersect is (10, 20) . It intersected point is the same with the x and y value when we solve the equation by using substitution method.
e. This means the price of each shirt is equals to $10 while the price of each pant is $20.
