Special taxes may be placed on an estate. true or false

What situation is an example of an observational study

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?

Can somebody 1. what is the formula for finding the vertical distance between two points on a coordinate plane?