Which question could the expression 1000n answer? Let n = the number of gallons of gas used. How many miles per gallon did the car get driving 1000 miles? Let n = the number of grams of food needed for each dog. How many grams of food are needed to feed 1000 dogs? Let n = the number of people at the show.
How many empty seats were there at the show if there are 1000 seats at the theater?

Let n = the number of seats at the theater.
How many empty seats will there by if 1000 people come to the show?

Let n = the number of grams of food needed for each dog. How many grams of food are needed to feed 1000 dogs?

Step-by-step explanation:

Let's analyze the 4 situations:

1) Let n = the number of gallons of gas used. How many miles per gallon did the car get driving 1000 miles?  NO

The answer to this question is

In fact for instance, if n = 500 (500 gallons used for 1000 miles), it means that the car uses miles/gallon.

Let n = the number of grams of food needed for each dog. How many grams of food are needed to feed 1000 dogs?  YES

In fact, the amount of grams of food needed to feed the 1000 dogs is given by the number of grams needed for each dog (n) times the number of dogs (1000), so:

Let n = the number of people at the show.  How many empty seats were there at the show if there are 1000 seats at the theater?  NO

In this case, the answer is given by

Because n is the number of people at the show, so the number of empty seats is equal to 1000 (total number of seats) minus the number of seats occupied (n).

Let n = the number of seats at the theater.  How many empty seats will there by if 1000 people come to the show? NO

In this case, the answer is

Since we have to subtract the number of seats occupied (1000) from the total number of seats (n).