Ramendra purchased some watermelons for Rs. 1,500. He sold one-fourth of them at a loss of 12%. At what gain percentage should the remaining watermelons be sold so as to gain 25% on the whole transaction (correct to two decimal places)?

Correct option is A

Given:
Cost price of watermelons = Rs 1500
One-fourth sold at 12%loss
Formula Used:
Profit Percentage = $$\frac{\text{Profit}}{\text{Cost Price}} \times 100$$​​
Solution:
To get a overall profit of 25%, watermelons to be sold at
1500 + 25% of 1500
=1500+ 375
=1875
Loss of one fourth of watermelons
Cost price of one-fourth = $$\frac{1500}{4}$$​= Rs 375
Loss of 12%
Loss = 375 - 12% of 375
= 375 - 45
=330
Remaining watermelons to be sold for Rs 1875 -330 = Rs.1545
Cost price of remaining watermelons = Rs 1500-375 = Rs. 1125
Profit percentage = $$\frac{1545 - 1125}{1125} \times 100 = 37.33\%$$​​
Alternate method:
Lets CP of each one-fourth be Rs 100
Total parts CP Rs 400
Then SP = 125% of 400 = Rs500
​$$\frac{\text{SP}}{\text{CP}} = \frac{\left(1 \times 88\right) + \left(3 \times x\right)}{400} = \frac{500}{400} \\88 + 3x = 500 \\3x = 500 - 88 \\x = \frac{412}{3} = 137.33\%$$

So gain should be 37.33%