Goods and Services Tax (GST)

ICSE Class 10 · Mathematics · Chapter 1

What this chapter covers

What GST is and why it is shared
The prices that appear in a GST problem
Price paid by the consumer after CGST and SGST
GST with a discount on the list price
Computation of tax along a chain of sales
Profit and loss when GST is charged
Inverse cases: working back from the amount paid
Mixed problems on a chain of sales
Rounding and setting out answers

Key points

Goods and Services Tax (GST) is an indirect tax on goods and services, collected at each stage of sale and borne finally by the consumer.
On an intra-state sale, GST is split equally: CGST to the Centre and SGST to the state, each at half the GST rate.
GST is charged on the basic price, which is the list price minus the discount.
Price paid by the consumer = basic price + CGST + SGST = basic price × (100 + r)/(100).
On a bill with several items, find the tax item by item, because the rates may differ.
GST payable by a dealer = output tax - input tax; this is input tax credit.
At a single rate, a dealer's GST payable = r% of (his selling price - his cost price).
The total GST received by the government along a chain equals the GST on the final sale to the consumer.
Profit and loss are worked out from prices excluding tax; GST does not change a dealer's profit.
In inverse cases, basic price = tax-inclusive price × (100)/(100 + r); never subtract r% of the tax-inclusive price.

Questions answered

Define Goods and Services Tax, and state how it is divided on an intra-state sale.

Goods and Services Tax is an indirect tax on the supply of goods and services, collected at every stage of sale and finally borne by the consumer. On an intra-state sale it is divided equally into CGST, which goes to the Central Government, and SGST, which goes to the state government.

An article costing ₹4,500 is sold within a state at a GST rate of 12%. Find the CGST, the SGST and the total amount paid.

CGST = 6% of 4500 = 270, SGST = 270, total paid = 4500 + 540 = 5040, that is ₹5,040.

The list price of a jacket is ₹2,000. The shop allows a discount of 25%, and the GST rate is 18%. Find the amount the customer pays.

Basic price = 1500; GST = 18% of 1500 = 270; amount paid = 1770, that is ₹1,770.

Why is GST calculated on the price after discount and not on the list price?

GST is a tax on the value actually charged for the supply. The buyer never pays the discount, so there is no sale value on which to charge tax for that part.

A customer pays ₹2,940 for a set of books, including GST at 5%. Find the price before tax.

Basic price = 2940 × (100)/(105) = 2800, that is ₹2,800.

The basic price of an electric iron is ₹6,500 and the SGST on it is ₹585. Find the GST rate.

SGST rate = (585)/(6500) × 100 = 9%, so the GST rate is 18%.

A sells an article to B for ₹5,000, and B sells it to C for ₹6,500, both within the same state. The GST rate is 18%. Find the GST and the CGST paid by B to the government.

Output tax = 1170, input tax = 900, GST payable = 270; CGST payable = 135, that is ₹135.

The list price of a mattress is ₹12,500, and a buyer pays ₹13,275 including GST at 18%. Find the rate of discount.

Basic price = 13275 × (100)/(118) = 11250; discount = 1250; discount rate = 10%.

Past board exam questions

ICSE 2027 sample paper · 1 mark

A customer pays a total GST of ₹ 600 on an article in an intra-state sale, and the tax rate is 12%. The price of the article is:

₹ 2,000
₹ 3,000
₹ 5,000
₹ 7,200

Show answer

₹ 5,000

ICSE 2027 sample paper · 4 marks

A shopkeeper marked an article at ₹ 2000. The rate of GST on the article is 18%. The customer has only ₹ 1888 with him and he requests the shopkeeper to reduce the price so that he can buy the article at ₹ 1888 including GST. What percent discount must the shopkeeper give to do so?

Show answer

Let the reduced price (before GST) be ₹ x. x + 18% of x = 1888 ⇒ 1.18x = 1888 ⇒ x = ₹ 1600 Discount = ₹ 2000 − ₹ 1600 = ₹ 400 Discount % = (400)/(2000) × 100 = 20%

ICSE 2026 board paper · 1 mark

The marked price of a refrigerator is ₹ 12,000 and GST paid by the customer is ₹ 2,160. The rate of GST is:

Show answer

18%

ICSE 2026 sample paper · 1 mark

An article which is marked at ₹ 1,200 is available at a discount of 20% and the rate of GST is 18%. The amount of SGST is:

₹ 216.00
₹ 172.80
₹ 108.00
₹ 86.40

Show answer

₹ 86.40

ICSE 2026 sample paper · 4 marks

The following bill shows the GST rate and the marked price of articles: Rajdhani Departmental Store | S. No. | Item | Marked Price | Discount | Rate of GST | |---|---|---|---|---| | (a) | Dry fruits (1 kg) | ₹ 1200 | ₹100 | 12% | | (b) | Packed Wheat flour (5kg) | ₹ 286 | Nil | 5% | | (c) | Bakery products | ₹ 500 | 10% | 12% | Find the total amount to be paid (including GST) for the above bill.

Show answer

(a) Dry fruits: price after discount = 1200 − 100 = ₹ 1100; GST = 12% of 1100 = ₹ 132. (b) Wheat flour: price = ₹ 286; GST = 5% of 286 = ₹ 14.30. (c) Bakery products: price after discount = 500 − 10% of 500 = ₹ 450; GST = 12% of 450 = ₹ 54. Total price after discount = 1100 + 286 + 450 = ₹ 1836. Total GST = 132 + 14.30 + 54 = ₹ 200.30. Amount to be paid = 1836 + 200.30 = ₹ 2036.30.

ICSE 2026 board paper · 3 marks

The cost price of a TV set is ₹ 20,000. The shopkeeper marked it for ₹ 24,000. He sells it to a customer at a discount of 10% on the marked price. If the sale is intra-state and the rate of GST is 12%, find the: (a) discounted price of the TV set. (b) amount paid by the customer to clear the bill.

Show answer

(a) Discount = 10% of ₹ 24,000 = ₹ 2,400. Discounted price = ₹ 24,000 − ₹ 2,400 = ₹ 21,600. (b) GST = 12% of ₹ 21,600 = ₹ 2,592 (CGST ₹ 1,296 + SGST ₹ 1,296). Amount paid by the customer = ₹ 21,600 + ₹ 2,592 = ₹ 24,192.

ICSE 2025 compartment paper · 1 mark

The GST of an article is reduced from 12% to 5% and due to this, the price paid for the article is cut down by ₹14. The original price of the article is:

₹50
₹98
₹100
₹200

Show answer

₹200

ICSE 2025 sample paper · 1 mark

An article which is marked at ₹ 1200 is available at a discount of 20% and the rate of GST is 18%. The amount of SGST is:

₹ 216.00
₹ 172.80
₹ 108.00
₹ 86.40

Show answer

₹ 86.40