A car is moving along a straight line, say \(OP\) in the figure. It moves from \(O\) to \(P\) in \(18\) s and returns from \(P\) to \(Q\) in \(6.0\) s. The average velocity and average speed of the car in going from \(O\) to \(P\) and back to \(Q\) respectively are:

1. \(10\) m/s & \(10\) m/s

2. \(20\) m/s & \(30\) m/s 

3. \(20\) m/s & \(20\) m/s

4. \(10\) m/s & \(20\) m/s

The position of an object moving along \(x\)-axis is given by \(x=a+bt^2\), where \(a=8.5\) m, \(b=2.5 \text{ ms}^{-2}\) and \(t\) is measured in seconds. Its average velocity between \(t=2.0\) s and \(t=4.0\) s is:
1. \(10~\text{m/s}\)
2. \(15~\text{m/s}\)
3. \(20~\text{m/s}\)
4. \(25~\text{m/s}\)