In an entrance examination,Ritu scored $56\%$ marks,Smita scored $92\%$ marks,and Rina scored $634$ marks. The maximum marks of the examination are $875$. What are the average marks scored by all the three girls together?

During one year,the population of a town was increased by $5 \%$ and during the next year,the population decreased by $5 \%$. If the total population is $9975$ at the end of the second year,then what was the population size in the beginning of the first year?

$A$ man wills $40 \%$ of his wealth to his wife and the rest to his children. What percentage of the wealth willed to the wife do the children get?

If a number is increased by $20 \%$ and then reduced by $20 \%$,what is the net change in the number?

If the price of gold increases by $30 \%$,find by how much the quantity of ornaments must be reduced so that the expenditure may remain the same as before?

Half of $1$ per cent written as a decimal is