Question

free shopping with her mother they pay $2 per pound for tomatoes at the vegetable stand find the constant proportionality in this situation write an equation to represent the relationship

Answer 1

Equation would be y=2x

So how you would use it is let’s say they bought 10
So y=2(10) so 20 dollars for 10 pounds

Answer 2

$\bf \qquad \qquad \textit{direct proportional variation}\\\\\textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll}k=constant\ of\\\qquad variation\end{array}\\\\[-0.35em]\rule{34em}{0.25pt}$

$\bf \begin{array}{|cc|ll} \cline{1-2} \stackrel{x}{tomatoes~lbs}&\stackrel{y}{price}\\ \cline{1-2} 1&2\\ 2&4\\ 3&6\\ 4&8 \\ \cline{1-2} \end{array}~\hspace{5em} \begin{array}{llll} \textit{we know } \begin{cases} x=2\\ y=4 \end{cases}\implies 4=k2 \\\\\\ \cfrac{4}{2}=k\implies \blacktriangleright 2=k \blacktriangleleft \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill y=2x~\hfill$