A sum of ₹ 400 amounts to ₹ 480 in 4 years. What will it amount to if the rate of interest is increased by 2 %? 

The average of seven numbers is 18. If one of the number is 17 and if it is replaced by 31, then the average becomes: 

In the given figure if each of the outer circles have radii ‘R’, then the radius of the inner circle will be:

Raghu sold an article for Rs. 180 after allowing a 20% discount on its marked price. Had he not allowed any discount, he would have gained 20%. What is the cost price of the article?

A and B can do a piece of work in 20 days and 12 days respectively. A started the work alone and then after 4 days B joined him till the completion of the work. How long did the work last?

$$ \sqrt{.081×.484\over0.0064×6.25}=?$$

If $$ {x+{1\over x}=\sqrt{3}}$$ then $$ {x^{48}+x^{378\over7}+x^{726\over11}+x^{60}}$$ is equal to

 $${a\over b}={2\over3}$$ and $${b\over c}={4\over5}$$ then the ratio  $${a+b}\over {b+c}$$ equal to: