A tea seller used to make 50% of profit by selling tea at Rs. 9 per cup. When the cost of ingredients increased by 25%, he started selling tea at Rs. 10 per cup. What is his profit percentage now?

Answer: Option C

Selling price of tea = Rs. 9 per cup
Profit % = 50%
∴ Cost price of tea = 9 × $$\frac{100}{150}$$ = Rs. 6 per cup
New cost price of tea after 25% increased,
New cost price = 6 × $$\frac{125}{100}$$ = Rs. 7.50
New selling price = Rs. 10
∴ Profit = (10 - 7.5) = Rs 2.50
∴ Profit % $$=\frac{2.50}{7.50}\times 100=33\frac{1}{3}\%$$