On seeing the below display board outside Pearl Stationary Shop, Chetan enters the shop to buy the following items:

	Pen	Pencil	Rainbow cover notebook
Price	₹5 each	₹7 each	₹ 200 each
Discount	5% on a dozen pens	10% on 20 pencils	------
Premium	-	-	₹50 on each notebook
Items purchased	1 dozen	20 pencils	5
GST	18%	12%	12%

The shopkeeper handed over the bill to Chetan saying that he has given further discount of 2% on total bill. Chetan became so happy hearing about the discount that he did not check the bill until he reached home. He later found out that though shopkeeper has given 2% discount as promised, he had also mischarged uniform 18% GST on all the items.

(a) Calculate :

(i) total selling price of all the items as per the offers displayed on the board.

(ii) total amount to be paid by Chetan including GST with correct rates.

(iii) actual amount charged by the shopkeeper.

(b) Did the shopkeeper overcharge Chetan? Justify your answer

(a)

For pen :

No. of pens purchased = 12

Price of 12 pens = ₹5 × 12 = ₹60

Discount (D) : 5% on dozen pens.

$D = \dfrac{5}{100} \times 60 = 3.$

Price after discount = ₹ 60 - ₹ 3 = ₹ 57.

GST = 18% = $\dfrac{18}{100} \times 57$ = ₹ 10.26

Total price : ₹ 57 + ₹ 10.26 = ₹ 67.26

For pencil :

No. of pencils purchased = 20

Price of 20 pencils = ₹ 7 × 20 = ₹ 140

Discount (D) : 10% on 20 pencils.

$D = \dfrac{10}{100} \times 140 = ₹ 14.$

Price after discount = ₹ 140 - ₹ 14 = ₹ 126.

GST = 12% = $\dfrac{12}{100} \times 126$ = ₹ 15.12

Total price : ₹ 126 + ₹ 15.12 = ₹ 141.12

For notebook :

No. of notebooks purchased = 5

Price of 5 notebooks = ₹ 200 × 5 = ₹ 1000

Premium (P) : ₹ 50 on each notebook

Total premium : ₹ 50 × 5 = ₹ 250.

Price after premium = ₹ 1000 + ₹ 250 = ₹ 1250.

GST = 12% = $\dfrac{12}{100} \times 1250$ = ₹ 150.

Total price : ₹ 1250 + ₹ 150 = ₹ 1400.

(i) Total selling price of all items = ₹ 57 + ₹ 126 + ₹ 1250 = ₹ 1433.

Hence, total selling price = ₹ 1433.

(ii) Total price paid (including GST) = ₹ 67.26 + ₹ 141.12 + ₹ 1400 = ₹ 1608.38

Hence, total price paid (including GST) = ₹ 1608.38

(iii) On applying incorrect GST rates :

On pen :

Price after discount = ₹ 57.

GST = 18% = $\dfrac{18}{100} \times 57$ = ₹ 10.26

Total price : ₹ 57 + ₹ 10.26 = ₹ 67.26

On pencil :

Price after discount = ₹ 126.

GST = 18% = $\dfrac{18}{100} \times 126$ = ₹ 22.68

Total price : ₹ 126 + ₹ 22.68 = ₹ 148.68

For notebook :

Price after premium = ₹ 1250.

GST = 18% = $\dfrac{18}{100} \times 1250$ = ₹ 225.

Total price : ₹ 1250 + ₹ 225 = ₹ 1475.

When the GST rate is applied as 18% uniformly, bill need to be paid by Chetan :

= ₹ 1475 + ₹ 148.68 + ₹ 67.26

= ₹ 1690.94

Discount given on total bill = 2%

$\dfrac{2}{100} \times 1690.94$ = 33.82

Bill = ₹ 1690.94 - ₹ 33.82 = ₹ 1657.12

Hence, bill = ₹ 1657.12

(b) The bill should be of ₹ 1608.38 but instead it was of ₹ 1657.12

⇒ ₹ 1657.12 - ₹ 1608.38 = ₹ 48.78

Hence, the shopkeeper overcharged an amount of ₹ 48.78