Overview
This lesson covers how to calculate water and electricity bills using tariff blocks, including how to handle VAT (Value-Added Tax) in pricing questions.
Water Tariffs
- Tariffs are different pricing categories for resource usage (e.g., water measured in kiloliters; 1 kiloliter = 1,000 liters).
- Each tariff block covers a usage range and has its own price per kiloliter.
- Always start calculations from the lowest block and work upwards, allocating the correct usage to each block.
- To find total cost, multiply kiloliters used in each block by its rate and sum all blocks.
- If VAT is excluded, leave as is; if VAT must be included, multiply the sum by 1.15 (for 15% VAT) or by 1.14 (for 14%).
Water Tariff Examples
- For 33 kiloliters: allocate usage across each block, multiply, and sum for total (exclude VAT if asked).
- For 29 kiloliters: similar process, but add VAT at the end by multiplying the sum by 1.15.
- For 51 kiloliters: spread usage across all blocks, total up, then include VAT if needed.
Electricity Tariffs
- Electricity is measured in kilowatt hours (kWh), and rates are usually in cents per kWh.
- Process is the same as water: allocate usage in order through each block.
- Add results from each block, then convert cents to Rand by dividing by 100.
- If VAT is excluded, add it at the end by multiplying by 1.15.
Electricity Tariff Examples
- For 170 kWh: 120 kWh in the first block (multiply by rate), remainder in next, sum totals, convert to Rand.
- For 238 kWh: allocate 120, 60, and 58 across blocks, sum, convert, and add VAT.
- For 302 kWh: split usage into applicable blocks, sum, convert, and include VAT.
Exam-style Tariff Table
- Some tables list only how much is used in each block, not the range—sum usage directly as given.
- Calculate total for each segment, sum, and then apply the appropriate VAT percentage (e.g., 1.14 for 14% VAT).
Key Terms & Definitions
- Tariff — pricing structure with different costs for different usage ranges.
- Kiloliter (kL) — 1,000 liters, used for measuring water.
- Kilowatt hour (kWh) — unit for measuring electricity usage.
- VAT (Value-Added Tax) — a tax added to goods/services, often 14% or 15%.
- Block Tariff — a rate system where the price increases with higher usage.
Action Items / Next Steps
- Practice allocating usage across tariff blocks and calculating costs both with and without VAT.
- Review homework or assigned readings on tariff calculations if provided.