Question

. A car that increases its speed from 20 km/h to 100 km/h undergoes ____________________ acceleration.

Answer 1

You need a time frame for that change. If the car goes from 20 to 100 in 5 seconds, it has a higher acceleration than if it were to go from 20 to 100 in 25 seconds.
Otherwise, you could use\[a = \frac{ \Delta v }{ t }\]