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The marked price of a cooker is same at four shops I, II, III and IV. Shop I allows two successive discounts of 12% and 79%, shop II allows successive discounts of 33% and 19%, shop III allows successive discounts of 38% and 39% and shop IV allows successive discounts of 55%, 79%, and 34% on the marked price of the cooker. Which shop is selling the cooker at the lowest price? 3373
III
II
IV
I
IV
Calculate the effective percentage that remains after discounts (100тИТd). The shop with the lowest resulting multiplier factor will have the lowest selling price. Focus on the largest single discount rate in each set to eliminate higher options quickly.
Four shops offer different sets of successive discounts on the same marked price (MP). Shop I: 12% and 79%. Shop II: 33% and 19%. Shop III: 38% and 39%. Shop IV: 55%, 79%, and 34%.
Effective┬аSelling┬аPrice=MP├Ч(1тИТ100d1тАЛтАЛ)├Ч(1тИТ100d2тАЛтАЛ)├Ч...
Calculate the effective percentage that remains after discounts (100тИТd). The shop with the lowest resulting multiplier factor will have the lowest selling price. Focus on the largest single discount rate in each set to eliminate higher options quickly.
Students often add the discount percentages directly (12+79=91) instead of calculating successive impacts, which leads to incorrect comparisons.
Calculate Effective Multiplier for Shop I
Effective price ratio = (1тИТ0.12)├Ч(1тИТ0.79)=0.88├Ч0.21=0.1848.
0.88├Ч0.21=0.1848
Calculate Effective Multiplier for Shop II
Effective price ratio = (1тИТ0.33)├Ч(1тИТ0.19)=0.67├Ч0.81=0.5427.
0.67├Ч0.81=0.5427
Calculate Effective Multiplier for Shop III
Effective price ratio = (1тИТ0.38)├Ч(1тИТ0.39)=0.62├Ч0.61=0.3782.
0.62├Ч0.61=0.3782
Calculate Effective Multiplier for Shop IV
Effective price ratio = (1тИТ0.55)├Ч(1тИТ0.79)├Ч(1тИТ0.34)=0.45├Ч0.21├Ч0.66=0.06237.
0.45├Ч0.21├Ч0.66=0.06237
Compare and Conclusion
Comparing 0.1848,0.5427,0.3782, and 0.06237, the smallest factor is 0.06237, corresponding to Shop IV.
0.06237<0.1848<0.3782<0.5427
C is correct because Shop IV results in the lowest effective multiplier of 0.06237, meaning the customer pays the least compared to other shops.
This logic is identical to calculating compound interest depreciation where the 'amount' decreases after each successive application of the rate.