In the 50.1 mg/L dosage problem, what percentage of calcium hypochlorite tablets were taped to the pipe?

• A. 60%
• B. 64.5%
• C. 50%
• D. 70%

Answer: (B)

To hit a dosage of 50.1 mg/L, you figure out how much chlorine a fully taped tablet would contribute per liter and then scale down to the exact amount needed. Each calcium hypochlorite tablet releases a fixed amount of available chlorine into the water when taped to the pipe. The fraction of a tablet that must be taped is the ratio of the required dose per liter to that full-tape dose per liter. Using the problem’s data, this ratio evaluates to about 0.645, which is 64.5%. In other words, taping about 64.5% of a tablet to the pipe delivers the desired 50.1 mg/L.