If the cost price of 28 oranges is equal to selling price of 24 oranges, then the profit percentage is:

A 252 m long train is running at a speed of 125 km/h. What is the time (in seconds) in which it will pass a man who starts from the engine running at the speed of 17 km/h in the same direction as that of the train?

If tan⁴θ + tan²θ = 1, what is the value of 11 (cos⁴θ + cos²θ)?

Evaluate the following:

$\sqrt{2+\sqrt{2+\sqrt{2+2cos8\theta}}}$