identify each example as a discrete random variable or a continuous random variable.

-- average price of gas ... continuous.  An average can come out to be any number, with a huge string of decimal places.  There are no numbers it CAN'T be.

-- car's speed ... continuous.  Between zero and the car's maximum top speed, there are no numbers it CAN'T be.

-- number of cars ... discrete.  It has to be a whole number.  There can't be a half a car or 0.746 of a car passing through.  

-- number of phone calls ... discrete.  It has to be a whole number.  There can't be a half of a call or 0.318 of a call made.

-- salaries ... I'm a little fuzzy on this one.  The employer can set a person's salary to be anything he wants it to be.  If they want it to be a whole number, or ANY fraction, they can do it ... there's no number it CAN'T be.  BUT ... when it comes time to actually pay him, THAT has to be a whole number of pennies.  There are actually a lot of numbers that they CAN'T pay, because they can't give him half of a penny, or 0.617 of a penny.

So I'm going to say that salary is a discrete variable.  

Discrete Random Variable: number of cars, phone calls, and salaries.

Continuous: annual increase and car’s speed

Step-by-step explanation: I got this right on Edmentum.