The price of petrol is increased by 25%. By how much percent a car owner should reduce his consumption of petrol so that the expenditure on petrol would not be increased?

if 20% of A = 50% of B, then what percentage of A is B?

The length of a rectangle is in- creased by 10% and breadth de- creased by 10%. Then the area of the new rectangle is: 

If 80% of A=50% of B and B = x% of A, then the value of x is :