A tradesman sold and article at a loss of 20%. If the selling price had been increased by Tk. 100, there would have been a gain of 5%. What was the cost price of the article?

A Tk. 400

B Tk. 500

C Tk. 550

D Tk. 600

Correct Answer: Option A

after covering 20% loss he gained 5% so, he actually gained total=(20+5)%=25% here, 25%=100 tk so 100 %= 100x100/25=400 tk