Direction (66-70): What should come in place of the question mark(?) in the following number series?

729, 243, 81, 27, ?

In a regular polygon, the exterior and interior angles are in the ration 1:4.The number of sides of the polygon is

If cosec θ=1.25 then $$ {4 \ tanθ-5 \ cosθ + 1\over secθ+ 4cotθ-1}=?$$

The average of four consecutive even numbers is 15. The 2nd highest number is: 

∠A, ∠B, ∠C are three angles of a triangle. If ∠A -∠B =18°, ∠B – ∠C = 45°, then, ∠B, ∠A and ∠C are

A certain amount of money earns Rs. 540 as simple interest in 3 years. If it earns a compound interest of Rs. 376.20 at the same rate of interest in 2 years, find the amount.

Direction: What is the approximate value will come in place of the question mark(?) in the following questions?
5682 ÷ 63 × 36=? ×19

A motorboat whose speed is 20 km/h in still water takes 30 minutes more to go 24 km upstream than to cover the same distance downstream. If the speed of the boat in still water is increased by 2 km/h, then bow much time will it take to go 39 km downstream and 30 km upstream?