$$I.e\ what\ is\ \frac{x}{y}\cdot\frac{1}{z}$$
or
$$what\ is\ \frac{1}{y}\cdot\frac{z}{z}$$
Statement 1: x = y/2, and z = 2x/5
If x = y/2, then z = 2x/5
$$Therefore,\ \frac{x}{yx}=\frac{\frac{y}{2}}{2x\left(\frac{2x}{5}\right)}$$
$$\frac{x}{yx}=\frac{\frac{y}{2}}{\frac{4x^2}{5}}$$
$$\frac{x}{yx}=\frac{y}{2}\cdot\frac{5}{4x^2}$$
The exact value of 'y' and 'x' is unknown, hence, statement 1 is NOT SUFFICIENT.
Statement 2: x/z = 5/2, and 1/y = 1/10
Given that;
$$\frac{x}{yx}=\frac{1}{y}\cdot\frac{x}{z}$$
$$where\ \frac{1}{y}=\frac{1}{10}\ and\ \frac{x}{z}=\frac{5}{2}$$
$$then,\ \frac{x}{yz}=\frac{1}{10}\ \cdot\frac{5}{2}=\frac{1}{4}$$
$$\frac{x}{yz}=\frac{1}{4}$$
Statement 2 alone is SUFFICIENT.
Since only statement 2 alone is SUFFICIENT, then, option B is the correct answer.
