If the difference between CI and SI for 3 years at the rate of 10% is Rs 31. Find the principle.

What is the total CSA of cone whose radius is 3 cm and height is 4 cm? 

Sunil, Karim and Mohan are invested a certain amount in the ratio 1: 2: 3 and the ratio of investment at the end of year is 3 : 8: 18. Find the ratio of time for which they invested ?

Tina can complete a piece of work in 10 days. Mina is $$ 33 {1\over3}$$%  less efficient than Tina. How many days are required to both to complete the work.

Directions : What will come in the place of the question mark (?) in the following number series?

100 100   50  150  37.5 ?

Directions : What will come in the place of the question mark (?) in the following number series?

100  99  95  86  ? 

Directions : What will come in the place of the question mark (?) in the following number series?

1  2  6  15  31  ? 

Directions : What will come in the place of the question mark (?) in the following number series?

2  4  11  37  ?