Given:
Marked price (M.P) = Rs.50000
Formula used:
Effective discount = D1 + D2 - (D1 × D2)/100
Calculation:
First case:
D1 = 25% and D2 = 15%
Effective discount = 25 + 15 - (25 × 15)/100
⇒ 40 - 3.75 = 36.25%
Second case:
D1 = 20% and D2 = 20%
Effective discount = 20 + 20 - (20 × 20)/100
⇒ 40 - 4 = 36%
Third case:
D1 = 30% and D2 = 10%
Effective discount = 30 + 10 - (30 × 10)/100
⇒ 40 - 3 = 37%
∴ The correct option is 3.
Alternate MethodCalculation:-
First Shopkeeper:
Marked price of the article: Rs. 50,000
First discount: 25%
Calculation: Rs. 50,000 - (25% of Rs. 50,000) = Rs. 50,000 - Rs. 12,500 = Rs. 37,500
Second discount: 15%
Calculation: Rs. 37,500 - (15% of Rs. 37,500) = Rs. 37,500 - Rs. 5,625 = Rs. 31,875
Final price offered by the first shopkeeper: Rs. 31,875
Second Shopkeeper:
Marked price of the article: Rs. 50,000
First discount: 20%
Calculation: Rs. 50,000 - (20% of Rs. 50,000) = Rs. 50,000 - Rs. 10,000 = Rs. 40,000
Second discount: 20%
Calculation: Rs. 40,000 - (20% of Rs. 40,000) = Rs. 40,000 - Rs. 8,000 = Rs. 32,000
Final price offered by the second shopkeeper: Rs. 32,000
Third Shopkeeper:
Marked price of the article: Rs. 50,000
First discount: 30%
Calculation: Rs. 50,000 - (30% of Rs. 50,000) = Rs. 50,000 - Rs. 15,000 = Rs. 35,000
Second discount: 10%
Calculation: Rs. 35,000 - (10% of Rs. 35,000) = Rs. 35,000 - Rs. 3,500 = Rs. 31,500
Final price offered by the third shopkeeper: Rs. 31,500
First shopkeeper: Rs. 31875
Second shopkeeper: Rs. 32000
Third shopkeeper: Rs. 31500
From the above calculations, the customer gets the most profit from the third shopkeeper, where the final price is Rs. 31,500. Therefore, the correct answer is 3) Third.