The simple interest on an amount at the rate of 7 percent for five years is Rs 700. So how much is the principal?

A right circular cone of largest volume is cut out from a solid wooden hemisphere. The remaining material is what percentage of the volume of the original hemisphere?

Direction: Study the following information and answer the related questions. P, Q, R, S, T, A, B, C, D and E are employees of a company. A table shows the average age of any two employees of the company. The average age of A and B is 27.5.
i.e. average age of A & P is given as (A+P)/2=39.5

What is the average age of D, R and S?

To cover a certain distance with a speed of 60 km/hr, a train takes 15 hours. If covers the same distance in 12 hours, what will be its speed?

The speed of two trains are in the ratio 6 : 7. If the second train covers 364 km in 4 hours, then what is the speed of the first train?

Direction: The given Bar Graph Presents the number of different types of vehicles (in lakhs) exported by a company during 2014 and 2015.

What is the ratio of the total number of type A and c vehicles exported in 2014 to the total number of type B and E vehicles exported in 2015? 

The L.C.M and H.C.F of the two numbers are 84 and 21 respectively. If the numbers have a ratio of 1: 4, what is the larger number?

If $$ {x^{4}+x^{2}y^{2}+y^{4}={21\over256}}$$ and $$ {x^{2}+xy+y^{2}={3\over16}}$$ then $$ {2(x^{2}+y^{2})}=?$$