Answer:
See below!
Step-by-step explanation:
I don't think you included the entire question, but maybe you were just stuck on this part, so I'm happy to help!
You include variables in a math equation to give meaning to a word, phrase, or situation in a shortened way.
For example, if I say, "I run 2 miles every day. How many miles will I run in x days?", your equation should look like this:
miles=2x
Notice that the 2 is a number, because that is the one thing that we know for sure. We know, no matter what, I run 2 miles a day. However, we don't know for how many days. So, for this, we need to put something as a sort of placeholder until we are told how many days.
Variables can be any letter, from A-Z! It is reccomended to stay with letters that avoid s, and i(among others) to make sure that you are using letters that can't be mistaken as letter on accident. For example, s could look like 5. In some cases, i could look like 1.
For your question, you could use:
#of cars=x
#of trucks/vans=y
