A sodium hypochlorite tank's full working capacity is 23,000 gallons. Its current level is at 1,200 gallons. How many gallons does the delivery driver need to add to bring it to 70% capacity?

To determine how many gallons the delivery driver needs to add to reach 70% capacity of the tank, it's important to first calculate what 70% of the tank's full capacity is.

The full working capacity of the sodium hypochlorite tank is 23,000 gallons. To find 70% of this capacity, you would perform the following calculation:

70% of 23,000 gallons = 0.70 × 23,000 = 16,100 gallons.

The current level in the tank is 1,200 gallons. To find out how many gallons need to be added to reach 70% capacity, the next step is to subtract the current level from the target level:

16,100 gallons (target) - 1,200 gallons (current) = 14,900 gallons.

Thus, the delivery driver must add 14,900 gallons to elevate the tank's level to 70% of its capacity. This calculation underscores the importance of understanding tank capacity and current levels for proper maintenance and safety in using chemicals like sodium hypochlorite.