A number when increased by 30% becomes 520. What is the number?

If the price of sugar is increased by 20%, by how much percent must a family reduce its consumption so that their expenditure increases by only 8%?

In a test, a student scores 20% and fails by 50 marks. Another student scores 40% and gets 30 marks more than the passing marks. Find the maximum marks.

The length and breadth of a rectangle are in the ratio 3:2. If the length is increased by 20% and the breadth is decreased by 10%, what is the percentage change in its perimeter?