The number of customers that enter a store during one day in an example of :

-a continuous random variable

-a discrete random variable

-either a continuous or a discrete random variable, depending on the number of the customers

-either a continuous or a discrete random variable, depending on the gender of the customers

a discrete random variable

Step-by-step explanation:

You can only have a natural number of clients entering the store.

For example, 0 clients, 1 client, 2 clients, 100 clients, ...

You cannot have a decimal value, for example, 0.5 clients.

So the correct answer is:

a discrete random variable

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.