A car travel at 30km hr for 1 hr then at some for 3hr that at 100km for 2 hr and 30km for 1hr

The general equation for average speed  v¯ , given a certain total distance  d  and total time  t , is

v¯= d/t .

We are given two distances over two different amounts of time. We simply calculate

v¯=30/1 + 40/2 =70/3 = 23 1/3 .

So, we can conclude that the average speed is  23.333…  km/h, or  23  km/h to 2 significant figures.

number of electrons for neutral cl