Join 60,000+ competitive exam aspirants
A trader lost 20% by selling a watch for ₹1,024. What percentage will he gain by selling it for ₹1,472?
15%
10%
20%
12%
15%
Use ratio of selling prices: SP1SP2=1,0241,472=1.4375. Since SP1 represents 80% of Cost Price, SP2 represents 80×1.4375=115%. Gain = 115%−100%=15%.
Loss percentage = 20%, Selling Price 1 = ₹1,024, Selling Price 2 = ₹1,472.
CP=1−Loss%SP,Gain%=CPSP−CP×100
Use ratio of selling prices: SP1SP2=1,0241,472=1.4375. Since SP1 represents 80% of Cost Price, SP2 represents 80×1.4375=115%. Gain = 115%−100%=15%.
Many students calculate the gain percentage on the Selling Price instead of the Cost Price, leading to incorrect values.
Calculate Cost Price (CP)
Since selling at ₹1,024 results in a 20% loss, the SP is 80% of the CP.
CP=0.801,024=1,280
Determine Profit for new SP
Calculate the difference between the new selling price and the cost price.
Profit=1,472−1,280=192
Calculate Gain Percentage
Divide profit by CP and multiply by 100 to get the gain percentage.
Gain%=(1,280192)×100=15%
A is correct because the calculated cost price is ₹1,280 and selling it for ₹1,472 results in a profit of ₹192, which is 15% of the cost price.
This ratio-based approach is similar to finding effective percentage changes in compound interest or successive discounts.