The percentage of metals in a mine of lead ore is $60 \%$. Now, the percentage of silver is $3/4 \%$ of the metals and the rest is lead. If the mass of ore extracted from this mine is $8000 \, kg$, what is the mass (in $kg$) of lead?

In an examination,there are $1000$ boys and $800$ girls. $60 \%$ of boys and $40 \%$ of girls passed. The percentage of candidates that failed is: (in $\%$)

The production of a company has ups and downs every year. The production increases for two consecutive years consistently by $15 \%$ and in the third year it decreases by $10 \%$. Again in the next two years it increases by $15 \%$ each year and decreases by $10 \%$ in the third year. If we start counting from the year $1998$,approximately what will be the effect on the production of the company in $2002$?

The population of Delhi two years ago was $55000$. It increased by $12 \%$ in the first year and decreased by $15 \%$ in the second year. What was the population of the town at the end of $2$ years?

The sum of the number of boys and girls in a school is $150$. If the number of boys is $x$,then the number of girls becomes $x\%$ of the total number of students. The number of boys is

In a test,a candidate secured $468$ marks out of maximum marks $A$. If the maximum marks $A$ were converted to $700$ marks,he would have secured $336$ marks. What were the maximum marks of the test?