ICSE Class 10 Mathematics • Chapter 01
GST (Goods and Services Tax): A comprehensive indirect tax imposed on the supply of goods and services in India, introduced on 1st July 2017.
Purpose: To replace multiple cascading taxes with a single unified tax system ("One Nation, One Tax").
| Term | Meaning |
|---|---|
| Listed Price / Marked Price (M.P.) | Original price printed on product by manufacturer |
| Discount | Reduction given on marked price (always on M.P.) |
| Sale Price / Cost Price | Price after discount, before adding GST |
| GST | Tax added on the sale price |
| Bill Amount / Invoice Amount | Final amount = Sale Price + GST |
| Intra-state | Transaction within the same state |
| Inter-state | Transaction between different states |
GST is split into two equal parts:
Example: If GST = 18%, then CGST = 9% and SGST = 9%
Only one tax is charged:
Example: If GST = 18%, then IGST = 18%
| Criteria | Intra-State | Inter-State |
|---|---|---|
| Transaction Type | Within same state | Between different states |
| Tax Components | CGST + SGST | IGST only |
| Tax Split | 50% + 50% | 100% to Centre |
| Example (18% GST) | 9% CGST + 9% SGST | 18% IGST |
Step 1: Calculate Sale Price (SP)
$\text{SP} = \text{Marked Price} - \text{Discount}$
$\text{Discount} = \frac{\text{Discount \%}}{100} \times \text{M.P.}$
Step 2: Calculate GST Amount
$\text{GST Amount} = \frac{\text{GST Rate}}{100} \times \text{SP}$
Step 3: Calculate Bill Amount
$\text{Bill Amount} = \text{SP} + \text{GST Amount}$
or $\text{Bill Amount} = \text{SP} \times \left(1 + \frac{\text{GST Rate}}{100}\right)$
If GST = 18%, then Bill = SP × 1.18
If GST = 12%, then Bill = SP × 1.12
If GST = 5%, then Bill = SP × 1.05
Problem: A TV has marked price ₹40,000. The shopkeeper gives 10% discount and charges 18% GST. Find:
(a) Sale price (b) CGST and SGST (c) Bill amount
Solution:
| Step | Calculation | Amount |
|---|---|---|
| Marked Price | Given | ₹40,000 |
| Discount (10%) | $\frac{10}{100} \times 40000$ | ₹4,000 |
| Sale Price | 40000 − 4000 | ₹36,000 |
| GST (18%) | $\frac{18}{100} \times 36000$ | ₹6,480 |
| CGST (9%) | $\frac{9}{100} \times 36000$ | ₹3,240 |
| SGST (9%) | $\frac{9}{100} \times 36000$ | ₹3,240 |
| Bill Amount | 36000 + 6480 | ₹42,480 |
When Bill Amount is given, find Sale Price:
$\text{Sale Price} = \frac{\text{Bill Amount} \times 100}{100 + \text{GST Rate}}$
Finding GST from Bill:
$\text{GST} = \frac{\text{Bill Amount} \times \text{GST Rate}}{100 + \text{GST Rate}}$
Example 2: The bill amount for a laptop including 18% GST is ₹59,000. Find the original price and GST charged.
Solution:
Sale Price = $\frac{59000 \times 100}{100 + 18} = \frac{5900000}{118} = ₹50,000$
GST = 59000 − 50000 = ₹9,000
Or: GST = $\frac{59000 \times 18}{118} = ₹9,000$
Input Tax Credit (ITC): The GST paid on purchases (input) can be deducted from the GST collected on sales (output).
Net GST Payable = Output Tax − Input Tax
Key Rule: ITC is allowed only when both transactions are of the same type:
Problem: A dealer in Delhi buys goods worth ₹1,00,000 from a manufacturer in Delhi and sells the same goods for ₹1,50,000 to a consumer in Delhi. If GST rate is 12%, find:
(a) GST paid by dealer to manufacturer
(b) GST charged by dealer from consumer
(c) Net GST payable by dealer to government
Solution:
| Transaction | Amount | GST (12%) | CGST (6%) | SGST (6%) |
|---|---|---|---|---|
| Purchase (Input) | ₹1,00,000 | ₹12,000 | ₹6,000 | ₹6,000 |
| Sale (Output) | ₹1,50,000 | ₹18,000 | ₹9,000 | ₹9,000 |
| Net GST Payable | ₹6,000 | ₹3,000 | ₹3,000 |
CGST Payable = 9000 − 6000 = ₹3,000 (to Central Govt)
SGST Payable = 9000 − 6000 = ₹3,000 (to State Govt)
Total Net GST = ₹6,000
Example 4: A manufacturer sells goods to a wholesaler for ₹5,000. The wholesaler sells to a retailer for ₹6,000. The retailer sells to consumer for ₹7,000. GST = 18%. Find tax paid at each stage and total tax revenue.
| Stage | Sale Price | GST Collected | ITC | Net GST Paid |
|---|---|---|---|---|
| Manufacturer → Wholesaler | ₹5,000 | ₹900 | Nil | ₹900 |
| Wholesaler → Retailer | ₹6,000 | ₹1,080 | ₹900 | ₹180 |
| Retailer → Consumer | ₹7,000 | ₹1,260 | ₹1,080 | ₹180 |
| Total Government Revenue | ₹1,260 | |||
Observation: Total GST = 18% of final sale price = 18% × 7000 = ₹1,260 ✓
| Rate | Items |
|---|---|
| 0% | Milk, fresh fruits, vegetables, bread, salt, books |
| 5% | Sugar, tea, coffee, edible oils, medicines |
| 12% | Processed food, computers, mobile phones |
| 18% | Electronics, machinery, most services |
| 28% | Luxury items, cars, tobacco, aerated drinks |
| To Find | Formula |
|---|---|
| Discount | $\frac{\text{Discount \%}}{100} \times \text{M.P.}$ |
| Sale Price | M.P. − Discount |
| GST Amount | $\frac{\text{GST \%}}{100} \times \text{S.P.}$ |
| Bill Amount | S.P. + GST = S.P. × $\left(1 + \frac{\text{GST}}{100}\right)$ |
| S.P. from Bill | $\frac{\text{Bill} \times 100}{100 + \text{GST \%}}$ |
| CGST / SGST | $\frac{\text{GST Rate}}{2}$ (for intra-state) |
| Net GST | Output Tax − Input Tax |
BOARD A shopkeeper buys a camera from a wholesaler for ₹10,000 and sells it to a customer for ₹15,000. If the rate of GST is 12%, find the GST paid by the shopkeeper to the Central Government.
BOARD The marked price of an article is ₹5,000. A shopkeeper allows a discount of 10% and sells it to a consumer. If GST is charged at 18%, find: (i) Discount (ii) Sale price (iii) CGST and SGST (iv) Bill amount
HOTS A manufacturer in Karnataka sells goods worth ₹80,000 to a dealer in Tamil Nadu. The dealer sells the same goods to a consumer in Tamil Nadu for ₹1,00,000. If GST = 18%, find the net CGST and SGST payable by the dealer.