Me and my friend really don't understand this. If anyone can help within 5 minutes, it'd help a lot. Thanks :)

the ratio is 18:81

Step-by-step explanation:

Okay so when a question is asking for a ratio it is basically asking a number compared to another:

So if you had 14 green frosted cupcakes and 8 blue frosted cupcakes what is the ratio of total frosted cupcakes to blue cupcakes:

the answer would be 22:8

Because you are trying to compare the total number of cupcakes to the blue cupcakes.

So back to your equation it wants to know the ratio between empty spots and the total number of parking spaces

Since we know that 63 of the spots have cars and 18 spots are empty we are going to add 63 and 18 together to get the total amount of parking spaces:

18 + 63 = 81

And since they want to know the empty spots compared to the total number of parking spaces we are going to be putting 18:81.

Hope this helped you!!!