Question

Mark's soup recipe makes 6 servings and uses 4 carrots and 2 potatoes.
Drag carrots and potatoes into the box to show how many Mark needs for 15 servings

Answer 1

The answer is 5 potatoes and 10 carrots.

Please enter this into desmos.com/calculator (a virtual graphing calculator that is awesome) and the x-intercept will be your answer.

Simply enter $\frac{6}{2}=\frac{15}{x}$ into one equation and $\frac{6}{4}=\frac{15}{x}$ into another equation. The x-intercepts are your answers, so $x$ = 5 and $x$ = 10.