Help me on this i wanna pass so do not answer for points or you get banned

When you drop a pebble from height a it reaches the ground with speed v if there is no air resistance. from what height should you drop it so it will reach the ground with three times the speed? (a) 9m (b) 3m (c) 6m (d) 18m

Aplane travels 1000 miles in 5 hours .what is the planes average speed?

The frequencies refer to the sample data collected from a population of interest when performing a hypothesis test comparing two or more population proportions.