Define instantaneous speed.

Can average speed and instantaneous speed be equal? Explain.

If a body covers a distance $x$ with speed $v_1$ and then it covers another distance $x$ with speed $v_2$, find the average speed for the whole journey.

If a body travels for time $\text{'}t\text{'}$ with speed $v_1$ and then it further travels for time $\text{'}t\text{'}$ with speed $v_2$, find the average speed.

At a time when it is cloudy, there may be frequent thunder and lightning. You hear the sound of thunder after observing the lightning stroke. Can you answer why this happens? (Speed of sound in air$= 346 {\mathrm{ms}}^{-1}$).

If a body covers three equal distances with speeds $v_1$,$v_2$ and $v_3$ then what is the average speed of the body?

What is the difference between average speed and instantaneous speed?