If the find x:y:z is?

Find the value of ∠OBE=?

Which of the following statements is/are True?
I.
II.
III.

A man earns a profit of 60% when he sells an article at 4/3 of the original selling price. Find the percent profit he makes at original price.

The value of sec⁴ A (1 – sin⁴A) – 2tan²A is: 

A train travelling at 48 km/hr crosses an another train half of its length and travelling in opposite direction at 42 km/hr in 12 seconds. It also passes a railway platform in 45 seconds. The length of the railway platform Is

θ is equal to:-

If 999x + 888y = 1332 and 888 x + 999y = 555.then the value of (x + y) is-