If  $$\sqrt{a}+\sqrt{b}=15 \ and \ (\sqrt{a}-\sqrt{b} )=3$$ then the value of $$\sqrt{ab/4} $$ is 

Direction : What value should come in the place of question mark (?) in the following questions?

11283 + 25 % of ? + 727 = 13280 

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 ?

8 men working for 9 hours a day complete a piece of work in 20 days. In how many days can 7 men working for 10 hours a day complete the same piece of work?

The average of 100 numbers is 44. The average of these 100 numbers and 4 other new numbers is 50. The average of the four new numbers will be

The sum of the ages of a father and son is 45 years. Five years ago, the product of their ages was 34. The present ages of father and son are _______, respectively.

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 age of T?

An alloy of copper and aluminum has 40% copper. Another alloy of Copper and Zinc has Copper and Zinc in the ratio 2: 7. These two alloys are mixed in ratio 5:3. Quantity of aluminum is what percent more/less than the quantity of copper in final alloy.