If the diameter of a wire is decreased by 10% by how much per cent (approximately) will the length be increased to keep the volume constant?

In a school, number of girls is 75% of number of boys. Difference between boys and girls is 30. On a particular day 20% girls were absent, then find the number of girls those who present? 

A number, on subtracting 15 from it reduces to its 80 %. What is 40 % of the number? 

The hourly wages of a mason have increased by 25%. Since the increase, the number of hours he works daily has reduced by 16%. If he was earning Rs. 120 per day before the increase, how much (in Rs.) is he earning now?

A reduction of 20% in the price of wheat a person enables to purchase 4 kg more for Rs. 160. Find the original price of wheat?

Population of a city is 7000. In next year the population is increased by 8%, then find the new population?

A shopkeeper has certain number of eggs of which 5% are found to be broken. He sells 93% of the remainder and still has 266 eggs left. How many eggs did he originally have?

A’s income is 60% of B’s income, and A’s expenditure is 70% of B’s expenditure. If A’s income is 75% of B’s expenditure, find the ratio of A’s saving to B’s saving?