The average of a collection of 20 measurements was calculated to be 56 cm . But later it was found that a mistake had occurred in one of the measurements which was recorded as 64 cm, but should have been 61 cm. The correct average must be: 

The cost price of 10 articles is equal to the selling price of 9 articles. Find the profit percent.

A started the business with the investment of Rs. 36000. B and C joined him with some investments after 3 and 6 months. The profit is divided in the ratio of 2 ∶ 3 ∶ 5 at the end of the year. Find the difference between the investment made by B and C in the business.

If the angle of the elevation of sun is θ and the length of the shadow of a pole of length P is S, then 

What is the LCM (least common multiple) of 57 and   93?

In ∆ABC, AC = BC and ∠BAC = 40°. If BC is extended to D such that BC = CD, find out ∠ADC = ?

A solid sphere of diameter 17.5 cm is cut into two equal halves. What will be the increase (in cm²) in the total surface area?

Find the value of n when $$ {n=\sqrt{n+ 2 \sqrt{n+2\sqrt{n+2\sqrt{3n}}}}}$$