Section 3.4: Currency & Money Calculations

Section 3.4: Currency & Money Calculations

While primary police work involves community safety and law enforcement, financial calculations are an integral part of station operations, equipment procurement, evidence processing, and multi-agency cost allocation. Police Officers and PSOs must accurately calculate costs, audit invoices, share training expenses, and apply discounts to maintain operational efficiency. The Victoria Police Entrance Examination tests these money-handling and currency calculation skills using realistic scenarios, aligning with the ACER numeracy subtest's Australian Core Skills Framework (ACSF) Level 3 parameters.

Unit Pricing and Procurement

In station administration, procurement officers regularly buy supplies in bulk. To compare the value of packages with different quantities and prices, you must calculate the unit pricing, which represents the cost of a single unit of an item.

The formula for unit pricing is:

$\text{Unit Price} = \frac{\text{Total Cost}}{\text{Quantity}}$

By finding the price per individual item, officers can determine which supplier offers the best value.

Worked Example: A station needs to buy high-visibility safety vests. Supplier A offers a pack of 12 vests for $780. Supplier B offers a pack of 18 vests for $1,116. Which supplier offers the better value?

• Supplier A unit cost: $\text{Unit Price} = \frac{\$780}{12} = \$65.00 \text{ per vest}$
• Supplier B unit cost: $\text{Unit Price} = \frac{\$1,116}{18} = \$62.00 \text{ per vest}$

Supplier B offers the lower unit cost of $62.00 per vest, making it the more cost-effective option for the station.

Invoicing and Goods and Services Tax (GST)

In Australia, the Goods and Services Tax (GST) is a broad-based tax of 10% on most goods, services, and other items sold or consumed. When purchasing equipment or auditing station invoices, officers must know how to add GST to a price or extract the GST component from a GST-inclusive price.

Adding 10% GST to a Price

To add GST to a pre-tax amount, multiply the price by 1.10. Worked Example: A local police youth program orders custom sporting shirts costing $450 before tax. What is the total GST-inclusive price?

$\text{Inclusive Price} = \$450 \times 1.10 = \$495.00$

Finding the GST Component from a GST-Inclusive Price

To find the amount of GST included in a total price, divide the total price by 11. Worked Example: A station receives an invoice of $1,650 for vehicle maintenance, which includes GST. How much GST was charged?

$\text{GST Component} = \frac{\$1,650}{11} = \$150.00$

The GST component is $150.00, meaning the pre-tax cost of the maintenance was $1,500.00 ($1,650.00 - $150.00).

Cost Sharing and Allocations

When multiple police commands, local councils, or government agencies coordinate on joint task forces (such as regional drug detection campaigns or emergency management training), they often share the expenses. Cost sharing divides a total bill among participating entities based on a predetermined ratio, such as their population sizes or staffing levels.

Worked Example: Three local police stations (A, B, and C) share the $18,000 cost of a joint community mobile patrol van. The cost is allocated based on the ratio of active officers in each station, which is 5:3:1. How much does Station A pay?

1. Total parts: $5 + 3 + 1 = 9 \text{ parts}$.
2. Value of one part: $$18,000 \div 9 = $2,000$.
3. Station A pays (5 parts): $5 imes $2,000 = $10,000$.
4. Station B pays (3 parts): $3 imes $2,000 = $6,000$.
5. Station C pays (1 part): $1 imes $2,000 = $2,000$. We check that the sum of the allocations ($10,000 + $6,000 + $2,000) equals the total cost of $18,000.

Percentage Discounts and Sales

Suppliers often offer bulk discounts or promotional markdowns on law enforcement gear. Calculating percentage discounts involves finding the discount amount and subtracting it from the original price, or multiplying the original price by the remaining percentage.

$\text{Discount Amount} = \text{Original Price} \times \left(\frac{\text{Discount Rate}}{100}\right)$ $\text{Sale Price} = \text{Original Price} - \text{Discount Amount}$

Alternatively:

$\text{Sale Price} = \text{Original Price} \times \left(1 - \frac{\text{Discount Rate}}{100}\right)$

Worked Example: A supplier offers a station a $15%$ discount on a bulk order of office chairs originally priced at $2,400. What is the final discounted price?

• Method 1 (Calculating discount first): $\text{Discount Amount} = \$2,400 \times 0.15 = \$360$ $\text{Sale Price} = \$2,400 - \$360 = \$2,040$
• Method 2 (Using remaining percentage): If the discount is 15%, the station pays 85% of the original price (100% - 15%): $\text{Sale Price} = \$2,400 \times 0.85 = \$2,040$

Both methods yield the same result of $2,040. Under timed test conditions, Method 2 is faster as it requires only a single multiplication step.

Financial Auditing and Discrepancy Reconciliation

In addition to procurement, police officers in administrative roles must regularly audit financial records to ensure accountability and prevent fraud. This involves verifying that invoices match purchase orders and reconciling discrepancies. When auditing, officers must cross-reference the total sum of individual line items against the final invoice amount, taking into account applied discounts and taxes.

For example, if a station orders three types of equipment:

• 10 protective vests at a unit price of $85.00 each
• 5 tactical flashlights at a unit price of $45.00 each
• 8 traffic cones at a unit price of $15.00 each

The pre-tax subtotal is calculated as: $\text{Subtotal} = (10 \times 85.00) + (5 imes 45.00) + (8 imes 15.00) = 850.00 + 225.00 + 120.00 = \$1,195.00$

If the vendor offers a 10% discount on the equipment subtotal before tax, the discounted subtotal becomes: $\text{Discounted Subtotal} = \$1,195.00 \times 0.90 = \$1,075.50$

Applying the 10% GST to this discounted amount: $\text{Total Invoice Amount} = \$1,075.50 \times 1.10 = \$1,183.05$

If the invoice lists the total as $1,185.00, an auditing officer would identify a discrepancy of $1.95. Documenting these audits requires precision and a clear understanding of order of operations, as taxes are typically applied after discounts are subtracted from the subtotal.