# ACC-0001 Response

## Approach

When a tax invoice includes GST, the total amount is 110% of the GST-exclusive price (100% base + 10% GST). To reverse-calculate the GST amount and the base price:

1. Divide the total by 1.1 to find the GST-exclusive price
2. Subtract the GST-exclusive price from the total to find the GST amount

## Calculations

**Given:**
- Invoice total (including GST): $1,100
- GST rate: 10%

**GST-exclusive price:**
$1,100 ÷ 1.1 = $1,000

**GST amount:**
$1,100 − $1,000 = $100

## Answers

**(a) GST amount included in the invoice: $100**

**(b) GST-exclusive price: $1,000**

**Verification:** $1,000 + (10% × $1,000) = $1,000 + $100 = $1,100 ✓