A sum of money becomes triple itself in 16 years. In how many years will it become 5 times at the same rate?

A vessel contains 20 litres of acid. 4 is taken out of the vessel and replaced by the same quantity of water. Next 4 litres of the mixture are withdrawn, and again the vessel is filled with the same quantity of water. Then find the ratio of acid left in the vessel with the quantity of acid initially in the vessel is:

Mohan gets 3 marks for each correct sum and loses 2 marks for each wrong sum. He attempts 30 sums and obtains 40 marks. The number of sums solved correctly is:

Direction (94-98): Study the following table to answer the given questions.
         Centre and Post-wise Numbered of candidate

In Kolkata, number of Specialist Officers is approximately what percent of that of Officers?

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

55 109 ? 433 865 1729