Sonu walked 25 m towards south and then took a left turn and walked 45 m. Again he took a left turn and walked 25 m. Finally he turned to his right and walked 20 m and stopped. How far and in which direction is Sonu from starting point?

Let the starting point be the origin $(0,0)$.
North is in the positive y-direction.
South is in the negative y-direction.
East is in the positive x-direction.
West is in the negative x-direction.

• Sonu walked 25 m towards south. Current position: $(0, -25)$. Direction: South.

• Then took a left turn and walked 45 m. From South, a left turn is East. Movement: 45 m East. Current position: $(0 + 45, -25) = (45, -25)$. Direction: East.

• Again he took a left turn and walked 25 m. From East, a left turn is North. Movement: 25 m North. Current position: $(45, -25 + 25) = (45, 0)$. Direction: North.

• Finally he turned to his right and walked 20 m. From North, a right turn is East. Movement: 20 m East. Current position: $(45 + 20, 0) = (65, 0)$. Direction: East.

The final position is $(65, 0)$.
The starting point was $(0,0)$.
The distance from the starting point is the magnitude of the displacement vector from $(0,0)$ to $(65,0)$.

Since the final position is $(65,0)$, which is along the positive x-axis relative to the origin, the direction is East.

Sonu is $\boxed{\text{65 m, East}}$ from the starting point.