If the profit is one-fourth of the selling price, find the true profit percentage on the cost price. MCQ with Answer and Explanation

Explanation:
Let CP = 100, MP = 150, SP = 150*0.75 = 112.5, profit = 12.5%.

Explanation:
Let CP = x. Loss 5% => SP1 = 0.95x. If sold at gain 10%, SP2 = 1.1x. Given 1.1x - 0.95x = 100 => 0.15x = 100 => x = 100/0.15 = 666.67, not in options. Wait, recalc: Difference = 15% of CP = 100 => CP = 100/0.15 = 666.67. But options are whole. Perhaps 500? Test: 0.15*500=75 not 100. 700 gives 105, close. But exact not in options. Let's adjust: maybe the gain would have been 10% more? Actually the problem says: if sold for Rs. 100 more, he would have gained 10% instead of loss 5%. The difference in percentage points is 15%, so 15% of CP = 100 => CP = 666.67. Not an option. So this question is flawed. I'll delete and regenerate another easy question.

Explanation:
CP = 320/0.8 = 400.