Points A, B, C, and D lie on a line, in that order. If AB=2 units, BC=5 units and AD=14 units, what is the ratio of AC to BD? Express your answer as a common fraction.

From looking at this, we can see that

CD = 14 - (2 + 5)

CD = 7

And...

AC = 2 + 5 = 7

BD = 5 + 7 = 12

So, the ratio of AC to BD = \(\frac{AC}{BD}\) = \(\frac{7}{12}\)