Find the value of $$\left({sin 35°\over cos55°} \right)^2+\left({cos55°\over sin 35°} \right)^2 \ -2 sin^{3}30°$$

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

$$ \sqrt{576}+\sqrt{841} =(?) $$

If 0.8 : X  :: 5 : 8 then X is equal to

If $$ {3x+}{2\over {\sqrt{x}}}=1$$ then $$ {x-{\sqrt{x}}}=?$$

The area of a circle, is 3850 sq.m. What will be its circumference?

There are three athletes A, B and C at a same point. A starts running from a point at a speed of 40 m/min. After 5 minutes, B starts running after A with a speed of 50 m/min. Simultaneously, C also starts running after A at 60 m/min. What distance has C covered (in m) when he catches A?

Product of digits of a 2-digit number is 27. If we add  54 to the number, the new number obtained is a number formed by interchange of the digits. Find the number.

A helicopter, at an altitude of 1500 metre, finds that two ships are sailing towards it, in the same direction. The angles of depression of the ships as observed from the helicopter are 60° and 30° respectively. Distance between the two ships, in metre is