Direction : What should come in place of the question (?) in the following question.

16  8    12   30  ?    472.5

The base of a right circular cone has the same radius a as that of a sphere. Both the sphere and the Cone have the same volume. Height of the cone is:

In the given figure, AB‖DC,  ∠BAD=90°,   ∠CBD=28° and ∠BCE=65°, Then ∠ABD=?

The ratio of marks obtained by Rajesh, Rakesh and Ramesh in an exam is 2 : 4 : 9. What are the marks obtained by Rakesh and Ramesh, if Rajesh scored 30 marks in the exam? 

A businessman sells a commodity at 10 % profit. If he had bought it at 10 % less and sold it for Rs. 2 less, then he would have gained $$16{2\over3}\%$$. The cost price of the commodity is 

The difference between the sum of four consecutive odd numbers and three consecutives even numbers together is 20. Also, the largest even number is 5 more than the largest odd number. What is the sum of the smallest odd number and the smallest even number?

Tarun and Uday together can complete a piece of work in 16 days; Uday and Vivek together can complete the work in 28 4/5 days; while Tarun and Vivek together can complete the work in 18 days. In how many days can Tarun alone complete the work?

A trader marked his goods at 20 % above the cost price. He sold half the stock at the marked price. one quarter at a discount of 20 % on the marked price and the rest at a discount of 40 % on the marked price. His total gain is