We see that we have conversion rates of [tex]\frac{12}{3} = 4[/tex] photos per minute, and thus [tex]\frac{1}{4} = 0.25[/tex] minutes per photo. I'll abbreviate photos as [tex]p[/tex] and minutes as [tex]m[/tex]. We have:
[tex]4 m \cdot \frac{4 p}{1 m} = 16 p[/tex]
[tex]24 p \cdot \frac{1 m}{4 p} = 6 m[/tex]
[tex]9 m \cdot \frac{4 p}{1 m} = 36 p[/tex]
[tex]40 p \cdot \frac{1 m}{4 p} = 10 m[/tex]
