When the price of an audio system was reduced by 20%, the sale increased by 80%. What was the net effect on the sale?

The sum of money that will yield Rs. 60 as simple interest at the rate of 6% per annum in 5 years is-

If u : v= 4 : 7 ,  v : w = 9 : 7 and u=72 then find the value of w.

If A’s income is 40 % less than that of B, how much percent B's income is more than that of A? 

Which of the following statements is/are True?
I. $$ {\sqrt{12}}>{^{3}{\sqrt{16}}}>{^{4}{\sqrt{24}}}$$
II. $$ ^{3}{\sqrt{25}}>{^{4}{\sqrt{32}}}>{^{6}{\sqrt{48}}}$$
III. $$ ^{4}{\sqrt{9}}>{^{3}{\sqrt{15}}}>{^{6}{\sqrt{24}}}$$

The line graph shows the number of vacancies of accountants in a certain company. Study the diagram and answer the following questions.

By what percent does the vacancies got increased in year 2016 from 2011?

simplify the following equation
$$ (1-{1\over3})(1-{1\over4})(1-{1\over5})......(1-{1\over n})$$

The following penalty diagram shows the 4 year exam results of the students of 10th standard. Study the diagram and answer the following questions.

State the percentage increase in the first division in the year 2003 as compared to the year 2002: