If 9 − 3x < 54, then which of the following must be true?

Greg had balloons to decorate inside the house.

Step-by-step explanation:

Lets say Greg has N number of balloons per box.

So, in total he had 2N balloons.

He used half of 2N to decorate the yard.

So, we have N balloons left.

Out of N, he used 40 to decorate his porch.

Then again the left number of balloons will be =

Therefore, Greg had balloons to decorate inside the house.