To find out how many mg of medication are delivered per half minute you can convert from hour to minutes
There are 60 minutes in 1 hour, so you can use the conversion factor (1h/60 min) and multiply the expression by it
15 mg/h (1h/60min) = 0.25 mg/min
But the question is per half minute so you have to multiply and divide the previous expression by 0.5 (To obtain 0.5 min in the denominator, which is half minute)
Then,
(0.25 mg/min ) (0.5/0.5) = 0.125 mg/ 0.5 min (0.125 mg per half minute)
So from what I understand, you would multiply 10m by 5m for the width to get 50m squared, and multiply the 50 by 2 to get 100m for both sides of the width for the pool. Next the length. Multiply 25m by 2.5m to get 62.5m squared. Once again, mutiply it by 2 for both side lengths of the pool to get 125m. Last, add 125m and 100m to get 225m for the concrete border of the pool.
