Peter invested a certain sum of money on simple interest whose value grew to Rs. 300 at the end of 3 years and to '400 at the end of another 5 years. What was the rate of interest in which he invested his sum?
A trader buys goods at a 19% discount on the label price. If he wants to make a profit of 20% after allowing a discount of 10%, by what % should his marked price be greater than the original label price?