Problems on Percentage

A candidate who gets $30\%$ of the marks in a test fails by $50$ marks. Another candidate who gets$320$ marks fails by $30$marks. Find the maximum marks?

When $120$ is deducted from $70\%$ of a number, the result is$90$. What is the number?

In an examination $95\%$ candidates passed and $600$ failed. How many students did appear in the examination?

In an examination $70\%$ of candidates passed in English, $80\%$ passed in Mathematics, $10\%$ failed in both subjects. If $144$ candidates passed in both the total number of candidates was:

$20\%$ of man's salary is paid as rent, $60\%$ as his living expenses and $10\%$ is paid in L.I.C. If he spends remaining $₹30$ on the education of the children. Find his salary.

If the price of a commodity is decreased by $20\%$ and its consumption is increased by $20\%$, what will be the increase or decrease in expenditure on the commodity?

Evaluate the expression:

$45\times ?=25\% of 900$

$40$ quintals are what percent of $2$ metric tonnes?

A milkman has $100$ litres of a mixture of milk and water, containing $20\mathrm{\%}$ of water. How much water must be added to make the water $40\mathrm{\%}$ of the new mixture?

$50 \mathrm{kg}$ is what percent of $250 \mathrm{kg}$$?$