Hi, I'm sure I'm doing something wrong here, I'm coming up with an exorbant amount of rainfall for ONE ROOF in a school. Somehow I don't think that in a drought-prone area it is feasable to expect the following to be true. I am unsure where I'm going wrong but its BUGGING me and I need to get this in tomorrow.

Calculate the annual amount of rainwater that would fall on the multipurpose building and calculate charges if Genesis had to use that amount of water

Monthly amount of rainfall on roof = rainfall mm x area covered
Note: Rainfall mm is taken from Question Nine and Area covered is the area of the roof worked out in Question Eight.
= 117.4 x 9267.84m²
= 117.4 x 85892858.27
= 117.4 x 85892858270mm
= 10083821560898mm
Note: I am now converting the mm amount into m³ and then I will convert this into KL
= 10083821560898÷ 1000
= 100838215608.98m
= ∛100838215608.98
= 4654.36774m³
→ 1KL = 1m³
= 4654.36774KL
Annual amount of rainfall on roof = monthly amount of rainfall on roof x 12
= 4654.36774 x 12
= 55852.41288 KL

Possible Water Charges = Usage Charges + Water Access Charges
Usage Charges = Consumption Charges + Government Bulk Water Charges
Note: Instead of multiplying the unit costs by the monthly water use I am multiplying per annum.
Consumption Charges = Annual Water Consumption x unit cost
= 55852.41288 x $0.62
= $34628.49599
Usage Charges = $34628.49599 + Government Bulk Water Charges
Government Bulk Water Charges = Annual Water Consumption x unit cost
= 44852.41288KL x $1.22
= $54719.94371
Usage Charges = $34628.49599 + $54719.94371
= $89348.4397
Possible Water Charges = $89348.4397 + Water Access Charge
Water Access Charge = Daily Rate x 365
Daily Rate = Net cost on sample bill ÷ bill period
= $38.81 ÷ 84days
≈ $0.46
Water Access Charge = $0.46 x 365
= $167.90
Possible Water Charges = $89348.4397 + $167.90
= $89516.3397
= $89516.34

The Annual cost of the rainfall on the multipurpose building would be approximately $89516.34.

2 answers

The area of the roof is ridiculous as you convert it.
Okay, am I doing my conversions wrong?