Question : Two rational numbers between $\frac{2}{3}$ and $\frac{5}{3}$ are :

1. $\frac{1}{6}$ and $\frac{2}{6}$
2. $\frac{1}{2}$ and $\frac{2}{1}$
3. $\frac{5}{6}$ and $\frac{7}{6}$
4. $\frac{2}{3}$ and $\frac{4}{3}$

Solution : 

Correct option is 3. $\frac{5}{6}$ and $\frac{7}{6}$

Changing the denominators of both numbers to 6, we get

$\frac{2}{3}=\frac{4}{6} \quad \& \quad \frac{5}{3}=\frac{10}{6}$

$\frac{5}{6} \& \frac{7}{6}$

So, correct answer is option 3.