Between two distinct rational numbers a and b, there exists another rational number which is :
A
$$\frac{a}{2}$$
B
$$\frac{b}{2}$$
C
$$\frac{ab}{2}$$
D
$$\frac{a + b}{2}$$
Correct Answer: $$\frac{a + b}{2}$$
If a and b are two rational numbers, then $$\frac{a + b}{2}$$ is a rational number lying between a and b.