16. The large rectangle $W X Y Z$ is divided into seven identical rectangles, as shown.
What is the ratio $W X: X Y$ ?
A $3: 2$
B $4: 3$
C $8: 5$
D $12: 7$
E $7: 3$
Solution
D

Let the longer side of each of the small rectangles be $p$ and let the shorter side be $q$. From the diagram, it can be seen that $3 p=4 q$ and hence $q=\frac{3}{4} p$. It can also be seen that the ratio $W X: X Y=3 p: p+q$. This is equal to $3 p: p+\frac{3}{4} p=3 p: \frac{7}{4} p=12 p: 7 p=12: 7$