Question : If the price of petrol is increased by 81%, by what percentage should the consumption of petrol be decreased by the consumer if the expenditure on petrol remains unchanged? (Correct to two decimal places).

Question : If the price of petrol is increased by 28%, by what percentage should the consumption be decreased by the consumer if the expenditure on petrol remains unchanged? (Correct to 2 decimal places)

Question : The numerator of a fraction is 6 less than its denominator. If the numerator is decreased by 1 and the denominator is increased by 5, then the denominator becomes 4 times the numerator. Find the fraction.

Question : What is the value of $\frac{7}{2}+\frac{11}{3}+\frac{7}{6}+\frac{11}{15}+\frac{7}{12}+\frac{11}{35}+\ldots \ldots+\frac{7}{156}+\frac{11}{575}$?

Question : If the radius of a sphere is increased by 2.5 decimetres (dm), then its surface area increases by 110 dm$^2$. What is the volume (in dm$^3$ ) of the sphere?
(Take $\pi=\frac{22}{7}$)