An article is sold at 20% profit. It its cost price is increased by Re 50 and at the same time if its selling price is also increases by Re 30. The percentage of profit decrease by ¹⁰/₃%. Find the cost price.

Solution(By Examveda Team)

SOLUTION:
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CASE I
Let initial cost price be x Rs.
Profit = 20/100 * x = x/5
So selling price = x + x/5 = 6x/5

CASE II
Cost price = x + 50
Selling Price = 6x/5 + 30
Profit = (6x/5 + 30) - (x + 50) = x/5 -20
Profit Percentage = (x/5 - 20) / (x + 50) * 100
But in according to the question profit percentage = 20 - 10/3 = 50/3 %
So (x/5 - 20) / (x + 50) * 100 = 50/3
∴ (x/5 - 20) / (x + 50) = 1/6
∴ 6x/5 - 120 = x + 50
∴ x/5 = 170
∴ x = 850
So original cost price = Rs 850