To find out how long the water in the cooler will last, we can set up an equation based on the amount of water being consumed.
- The total amount of water in the cooler is 1,280 ounces.
- The office workers consume 30 ounces of water per hour.
Let \( h \) represent the number of hours the water lasts. After \( h \) hours, the amount of water remaining can be represented as:
\[ 1,280 - 30h = 0 \]
This equation states that after \( h \) hours of consumption, the water in the cooler will be depleted to 0 ounces.
Thus, the correct equation is:
\[ \boxed{1,280 - 30h = 0} \]